Seal-forming structure of patient interface with multiple sealing materials

ABSTRACT

A patient interface includes a seal-forming structure constructed and arranged to form a seal with a region of the patients face surrounding an entrance to the patients airways. The seal-forming structure comprises a first section and a second section. The first section is constructed from a first material. The first section is configured to sealingly engage against a first region of the patients face. The second section is constructed from a second material that is different than the first material. The second section is configured to sealingly engage against a second region of the patients face. The second material is foam. The patient interface also includes a positioning and stabilising structure to provide a force to hold a seal-forming structure in a therapeutically effective position on a patient&#39;s head.

1 CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Australian Provisional PatentApplication No. 2020902681, filed Jul. 30, 2020, which is incorporatedherein by reference in its entirety.

2 BACKGROUND OF THE TECHNOLOGY 2.1 Field of the Technology

The present technology relates to one or more of the screening,diagnosis, monitoring, treatment, prevention and amelioration ofrespiratory-related disorders. The present technology also relates tomedical devices or apparatus, and their use.

2.2 Description of the Related Art

2.2.1 Human Respiratory System and its Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe inhaled air into the venous blood and carbon dioxide to move in theopposite direction. The trachea divides into right and left mainbronchi, which further divide eventually into terminal bronchioles. Thebronchi make up the conducting airways, and do not take part in gasexchange. Further divisions of the airways lead to the respiratorybronchioles, and eventually to the alveoli. The alveolated region of thelung is where the gas exchange takes place, and is referred to as therespiratory zone. See “Respiratory Physiology”, by John B. West,Lippincott Williams & Wilkins, 9th edition published 2012.

A range of respiratory disorders exist. Certain disorders may becharacterised by particular events, e.g. apneas, hypopneas, andhyperpneas.

Examples of respiratory disorders include Obstructive Sleep Apnea (OSA),Cheyne-Stokes Respiration (CSR), respiratory insufficiency, ObesityHyperventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease(COPD), Neuromuscular Disease (NMD) and Chest wall disorders.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterised by events including occlusion or obstruction ofthe upper air passage during sleep. It results from a combination of anabnormally small upper airway and the normal loss of muscle tone in theregion of the tongue, soft palate and posterior oropharyngeal wallduring sleep. The condition causes the affected patient to stopbreathing for periods typically of 30 to 120 seconds in duration,sometimes 200 to 300 times per night. It often causes excessive daytimesomnolence, and it may cause cardiovascular disease and brain damage.The syndrome is a common disorder, particularly in middle agedoverweight males, although a person affected may have no awareness ofthe problem. See U.S. Pat. No. 4,944,310 (Sullivan).

Cheyne-Stokes Respiration (CSR) is another form of sleep disorderedbreathing. CSR is a disorder of a patient's respiratory controller inwhich there are rhythmic alternating periods of waxing and waningventilation known as CSR cycles. CSR is characterised by repetitivede-oxygenation and re-oxygenation of the arterial blood. It is possiblethat CSR is harmful because of the repetitive hypoxia. In some patientsCSR is associated with repetitive arousal from sleep, which causessevere sleep disruption, increased sympathetic activity, and increasedafterload. See U.S. Pat. No. 6,532,959 (Berthon-Jones).

Respiratory failure is an umbrella term for respiratory disorders inwhich the lungs are unable to inspire sufficient oxygen or exhalesufficient CO₂ to meet the patient's needs. Respiratory failure mayencompass some or all of the following disorders.

A patient with respiratory insufficiency (a form of respiratory failure)may experience abnormal shortness of breath on exercise.

Obesity Hyperventilation Syndrome (OHS) is defined as the combination ofsevere obesity and awake chronic hypercapnia, in the absence of otherknown causes for hypoventilation. Symptoms include dyspnea, morningheadache and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a groupof lower airway diseases that have certain characteristics in common.These include increased resistance to air movement, extended expiratoryphase of respiration, and loss of the normal elasticity of the lung.Examples of COPD are emphysema and chronic bronchitis. COPD is caused bychronic tobacco smoking (primary risk factor), occupational exposures,air pollution and genetic factors. Symptoms include: dyspnea onexertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses manydiseases and ailments that impair the functioning of the muscles eitherdirectly via intrinsic muscle pathology, or indirectly via nervepathology. Some NMD patients are characterised by progressive muscularimpairment leading to loss of ambulation, being wheelchair-bound,swallowing difficulties, respiratory muscle weakness and, eventually,death from respiratory failure. Neuromuscular disorders can be dividedinto rapidly progressive and slowly progressive: (i) Rapidly progressivedisorders: Characterised by muscle impairment that worsens over monthsand results in death within a few years (e.g. Amyotrophic lateralsclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers);(ii) Variable or slowly progressive disorders: Characterised by muscleimpairment that worsens over years and only mildly reduces lifeexpectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic musculardystrophy). Symptoms of respiratory failure in NMD include: increasinggeneralised weakness, dysphagia, dyspnea on exertion and at rest,fatigue, sleepiness, morning headache, and difficulties withconcentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result ininefficient coupling between the respiratory muscles and the thoraciccage. The disorders are usually characterised by a restrictive defectand share the potential of long term hypercapnic respiratory failure.Scoliosis and/or kyphoscoliosis may cause severe respiratory failure.Symptoms of respiratory failure include: dyspnea on exertion, peripheraloedema, orthopnea, repeated chest infections, morning headaches,fatigue, poor sleep quality and loss of appetite.

A range of therapies have been used to treat or ameliorate suchconditions. Furthermore, otherwise healthy individuals may takeadvantage of such therapies to prevent respiratory disorders fromarising. However, these have a number of shortcomings.

2.2.2 Therapies

Various respiratory therapies, such as Continuous Positive AirwayPressure (CPAP) therapy, Non-invasive ventilation (NIV), Invasiveventilation (IV), and High Flow Therapy (HFT) have been used to treatone or more of the above respiratory disorders.

2.2.2.1 Respiratory Pressure Therapies

Respiratory pressure therapy is the application of a supply of air to anentrance to the airways at a controlled target pressure that isnominally positive with respect to atmosphere throughout the patient'sbreathing cycle (in contrast to negative pressure therapies such as thetank ventilator or cuirass).

Continuous Positive Airway Pressure (CPAP) therapy has been used totreat Obstructive Sleep Apnea (OSA). The mechanism of action is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion, such as by pushing the soft palate andtongue forward and away from the posterior oropharyngeal wall. Treatmentof OSA by CPAP therapy may be voluntary, and hence patients may electnot to comply with therapy if they find devices used to provide suchtherapy one or more of: uncomfortable, difficult to use, expensive andaesthetically unappealing.

Non-invasive ventilation (NIV) provides ventilatory support to a patientthrough the upper airways to assist the patient breathing and/ormaintain adequate oxygen levels in the body by doing some or all of thework of breathing. The ventilatory support is provided via anon-invasive patient interface. NIV has been used to treat CSR andrespiratory failure, in forms such as OHS, COPD, NMD and Chest Walldisorders. In some forms, the comfort and effectiveness of thesetherapies may be improved.

Invasive ventilation (IV) provides ventilatory support to patients thatare no longer able to effectively breathe themselves and may be providedusing a tracheostomy tube. In some forms, the comfort and effectivenessof these therapies may be improved.

2.2.2.2 Flow Therapies

Not all respiratory therapies aim to deliver a prescribed therapeuticpressure. Some respiratory therapies aim to deliver a prescribedrespiratory volume, by delivering an inspiratory flow rate profile overa targeted duration, possibly superimposed on a positive baselinepressure. In other cases, the interface to the patient's airways is‘open’ (unsealed) and the respiratory therapy may only supplement thepatient's own spontaneous breathing with a flow of conditioned orenriched gas. In one example, High Flow therapy (HFT) is the provisionof a continuous, heated, humidified flow of air to an entrance to theairway through an unsealed or open patient interface at a “treatmentflow rate” that is held approximately constant throughout therespiratory cycle. The treatment flow rate is nominally set to exceedthe patient's peak inspiratory flow rate. HFT has been used to treatOSA, CSR, respiratory failure, COPD, and other respiratory disorders.One mechanism of action is that the high flow rate of air at the airwayentrance improves ventilation efficiency by flushing, or washing out,expired CO₂ from the patient's anatomical deadspace. Hence, HFT is thussometimes referred to as a deadspace therapy (DST). Other benefits mayinclude the elevated warmth and humidification (possibly of benefit insecretion management) and the potential for modest elevation of airwaypressures. As an alternative to constant flow rate, the treatment flowrate may follow a profile that varies over the respiratory cycle.

Another form of flow therapy is long-term oxygen therapy (LTOT) orsupplemental oxygen therapy. Doctors may prescribe a continuous flow ofoxygen enriched gas at a specified oxygen concentration (from 21%, theoxygen fraction in ambient air, to 100%) at a specified flow rate (e.g.,1 litre per minute (LPM), 2 LPM, 3 LPM, etc.) to be delivered to thepatient's airway.

2.2.2.3 Supplementary Oxygen

For certain patients, oxygen therapy may be combined with a respiratorypressure therapy or HFT by adding supplementary oxygen to thepressurised flow of air. When oxygen is added to respiratory pressuretherapy, this is referred to as RPT with supplementary oxygen. Whenoxygen is added to HFT, the resulting therapy is referred to as HFT withsupplementary oxygen.

2.2.3 Respiratory Therapy Systems

These respiratory therapies may be provided by a respiratory therapysystem or device. Such systems and devices may also be used to screen,diagnose, or monitor a condition without treating it.

A respiratory therapy system may comprise a Respiratory Pressure TherapyDevice (RPT device), an air circuit, a humidifier, a patient interface,an oxygen source, and data management.

Another form of therapy system is a mandibular repositioning device.

2.2.3.1 Patient Interface

A patient interface may be used to interface respiratory equipment toits wearer, for example by providing a flow of air to an entrance to theairways. The flow of air may be provided via a mask to the nose and/ormouth, a tube to the mouth or a tracheostomy tube to the trachea of apatient. Depending upon the therapy to be applied, the patient interfacemay form a seal, e.g., with a region of the patient's face, tofacilitate the delivery of gas at a pressure at sufficient variance withambient pressure to effect therapy, e.g., at a positive pressure ofabout 10 cmH₂O relative to ambient pressure. For other forms of therapy,such as the delivery of oxygen, the patient interface may not include aseal sufficient to facilitate delivery to the airways of a supply of gasat a positive pressure of about 10 cmH₂O. For flow therapies such asnasal HFT, the patient interface is configured to insufflate the naresbut specifically to avoid a complete seal. One example of such a patientinterface is a nasal cannula.

Certain other mask systems may be functionally unsuitable for thepresent field. For example, purely ornamental masks may be unable tomaintain a suitable pressure. Mask systems used for underwater swimmingor diving may be configured to guard against ingress of water from anexternal higher pressure, but not to maintain air internally at a higherpressure than ambient.

Certain masks may be clinically unfavourable for the present technologye.g. if they block airflow via the nose and only allow it via the mouth.

Certain masks may be uncomfortable or impractical for the presenttechnology if they require a patient to insert a portion of a maskstructure in their mouth to create and maintain a seal via their lips.

Certain masks may be impractical for use while sleeping, e.g. forsleeping while lying on one's side in bed with a head on a pillow.

The design of a patient interface presents a number of challenges. Theface has a complex three-dimensional shape. The size and shape of nosesand heads varies considerably between individuals. Since the headincludes bone, cartilage and soft tissue, different regions of the facerespond differently to mechanical forces. The jaw or mandible may moverelative to other bones of the skull. The whole head may move during thecourse of a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being oneor more of obtrusive, aesthetically undesirable, costly, poorly fitting,difficult to use, and uncomfortable especially when worn for longperiods of time or when a patient is unfamiliar with a system. Wronglysized masks can give rise to reduced compliance, reduced comfort andpoorer patient outcomes. Masks designed solely for aviators, masksdesigned as part of personal protection equipment (e.g. filter masks),SCUBA masks, or for the administration of anaesthetics may be tolerablefor their original application, but nevertheless such masks may beundesirably uncomfortable to be worn for extended periods of time, e.g.,several hours. This discomfort may lead to a reduction in patientcompliance with therapy. This is even more so if the mask is to be wornduring sleep.

CPAP therapy is highly effective to treat certain respiratory disorders,provided patients comply with therapy. If a mask is uncomfortable, ordifficult to use a patient may not comply with therapy. Since it isoften recommended that a patient regularly wash their mask, if a mask isdifficult to clean (e.g., difficult to assemble or disassemble),patients may not clean their mask and this may impact on patientcompliance.

While a mask for other applications (e.g. aviators) may not be suitablefor use in treating sleep disordered breathing, a mask designed for usein treating sleep disordered breathing may be suitable for otherapplications.

For these reasons, patient interfaces for delivery of CPAP during sleepform a distinct field.

2.2.3.1.1 Seal-Forming Structure

Patient interfaces may include a seal-forming structure. Since it is indirect contact with the patient's face, the shape and configuration ofthe seal-forming structure can have a direct impact the effectivenessand comfort of the patient interface.

A patient interface may be partly characterised according to the designintent of where the seal-forming structure is to engage with the face inuse. In one form of patient interface, a seal-forming structure maycomprise a first sub-portion to form a seal around the left naris and asecond sub-portion to form a seal around the right naris. In one form ofpatient interface, a seal-forming structure may comprise a singleelement that surrounds both nares in use. Such single element may bedesigned to for example overlay an upper lip region and a nasal bridgeregion of a face. In one form of patient interface a seal-formingstructure may comprise an element that surrounds a mouth region in use,e.g. by forming a seal on a lower lip region of a face. In one form ofpatient interface, a seal-forming structure may comprise a singleelement that surrounds both nares and a mouth region in use. Thesedifferent types of patient interfaces may be known by a variety of namesby their manufacturer including nasal masks, full-face masks, nasalpillows, nasal puffs and oro-nasal masks.

A seal-forming structure that may be effective in one region of apatient's face may be inappropriate in another region, e.g. because ofthe different shape, structure, variability and sensitivity regions ofthe patient's face. For example, a seal on swimming goggles thatoverlays a patient's forehead may not be appropriate to use on apatient's nose.

Certain seal-forming structures may be designed for mass manufacturesuch that one design fit and be comfortable and effective for a widerange of different face shapes and sizes. To the extent to which thereis a mismatch between the shape of the patient's face, and theseal-forming structure of the mass-manufactured patient interface, oneor both must adapt in order for a seal to form.

One type of seal-forming structure extends around the periphery of thepatient interface, and is intended to seal against the patient's facewhen force is applied to the patient interface with the seal-formingstructure in confronting engagement with the patient's face. Theseal-forming structure may include an air or fluid filled cushion, or amoulded or formed surface of a resilient seal element made of anelastomer such as a rubber. With this type of seal-forming structure, ifthe fit is not adequate, there will be gaps between the seal-formingstructure and the face, and additional force will be required to forcethe patient interface against the face in order to achieve a seal.

Another type of seal-forming structure incorporates a flap seal of thinmaterial positioned about the periphery of the mask so as to provide aself-sealing action against the face of the patient when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to achieve a seal, or the mask mayleak. Furthermore, if the shape of the seal-forming structure does notmatch that of the patient, it may crease or buckle in use, giving riseto leaks.

Another type of seal-forming structure may comprise a friction-fitelement, e.g. for insertion into a naris, however some patients findthese uncomfortable.

Another form of seal-forming structure may use adhesive to achieve aseal. Some patients may find it inconvenient to constantly apply andremove an adhesive to their face.

A range of patient interface seal-forming structure technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT™ nasal pillows mask, SWIFT™ II nasal pillows mask,SWIFT™ LT nasal pillows mask, SWIFT™ FX nasal pillows mask and MIRAGELIBERTY™ full-face mask. The following patent applications, assigned toResMed Limited, describe examples of nasal pillows masks: InternationalPatent Application WO2004/073,778 (describing amongst other thingsaspects of the ResMed Limited SWIFT™ nasal pillows), US PatentApplication 2009/0044808 (describing amongst other things aspects of theResMed Limited SWIFT™ LT nasal pillows); International PatentApplications WO 2005/063,328 and WO 2006/130,903 (describing amongstother things aspects of the ResMed Limited MIRAGE LIBERTY™ full-facemask); International Patent Application WO 2009/052,560 (describingamongst other things aspects of the ResMed Limited SWIFT™ FX nasalpillows).

2.2.3.1.2 Positioning and Stabilising

A seal-forming structure of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming structure, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US PatentApplication Publication No. US 2010/0000534. However, the use ofadhesives may be uncomfortable for some.

Another technique is the use of one or more straps and/or stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

2.2.3.2 Respiratory Pressure Therapy (RPT) Device

A respiratory pressure therapy (RPT) device may be used individually oras part of a system to deliver one or more of a number of therapiesdescribed above, such as by operating the device to generate a flow ofair for delivery to an interface to the airways. The flow of air may bepressure-controlled (for respiratory pressure therapies) orflow-controlled (for flow therapies such as HFT). Thus RPT devices mayalso act as flow therapy devices. Examples of RPT devices include a CPAPdevice and a ventilator.

2.2.3.3 Air Circuit

An air circuit is a conduit or a tube constructed and arranged to allow,in use, a flow of air to travel between two components of a respiratorytherapy system such as the RPT device and the patient interface. In somecases, there may be separate limbs of the air circuit for inhalation andexhalation. In other cases, a single limb air circuit is used for bothinhalation and exhalation.

2.2.3.4 Humidifier

Delivery of a flow of air without humidification may cause drying ofairways. The use of a humidifier with an RPT device and the patientinterface produces humidified gas that minimizes drying of the nasalmucosa and increases patient airway comfort. In addition in coolerclimates, warm air applied generally to the face area in and about thepatient interface is more comfortable than cold air. Humidifierstherefore often have the capacity to heat the flow of air was well ashumidifying it.

2.2.3.5 Oxygen Source

Experts in this field have recognized that exercise for respiratoryfailure patients provides long term benefits that slow the progressionof the disease, improve quality of life and extend patient longevity.Most stationary forms of exercise like tread mills and stationarybicycles, however, are too strenuous for these patients. As a result,the need for mobility has long been recognized. Until recently, thismobility has been facilitated by the use of small compressed oxygentanks or cylinders mounted on a cart with dolly wheels. The disadvantageof these tanks is that they contain a finite amount of oxygen and areheavy, weighing about 50 pounds when mounted.

Oxygen concentrators have been in use for about 50 years to supplyoxygen for respiratory therapy. Traditional oxygen concentrators havebeen bulky and heavy making ordinary ambulatory activities with themdifficult and impractical. Recently, companies that manufacture largestationary oxygen concentrators began developing portable oxygenconcentrators (POCs). The advantage of POCs is that they can produce atheoretically endless supply of oxygen. In order to make these devicessmall for mobility, the various systems necessary for the production ofoxygen enriched gas are condensed. POCs seek to utilize their producedoxygen as efficiently as possible, in order to minimise weight, size,and power consumption. This may be achieved by delivering the oxygen asseries of pulses or “boli”, each bolus timed to coincide with the startof inspiration. This therapy mode is known as pulsed or demand (oxygen)delivery (POD), in contrast with traditional continuous flow deliverymore suited to stationary oxygen concentrators.

2.2.3.6 Data Management

There may be clinical reasons to obtain data to determine whether thepatient prescribed with respiratory therapy has been “compliant”, e.g.that the patient has used their RPT device according to one or more“compliance rules”. One example of a compliance rule for CPAP therapy isthat a patient, in order to be deemed compliant, is required to use theRPT device for at least four hours a night for at least 21 of 30consecutive days. In order to determine a patient's compliance, aprovider of the RPT device, such as a health care provider, may manuallyobtain data describing the patient's therapy using the RPT device,calculate the usage over a predetermined time period, and compare withthe compliance rule. Once the health care provider has determined thatthe patient has used their RPT device according to the compliance rule,the health care provider may notify a third party that the patient iscompliant.

There may be other aspects of a patient's therapy that would benefitfrom communication of therapy data to a third party or external system.

Existing processes to communicate and manage such data can be one ormore of costly, time-consuming, and error-prone.

2.2.3.7 Mandibular Repositioning

A mandibular repositioning device (MRD) or mandibular advancement device(MAD) is one of the treatment options for sleep apnea and snoring. It isan adjustable oral appliance available from a dentist or other supplierthat holds the lower jaw (mandible) in a forward position during sleep.The MRD is a removable device that a patient inserts into their mouthprior to going to sleep and removes following sleep. Thus, the MRD isnot designed to be worn all of the time. The MRD may be custom made orproduced in a standard form and includes a bite impression portiondesigned to allow fitting to a patient's teeth. This mechanicalprotrusion of the lower jaw expands the space behind the tongue, putstension on the pharyngeal walls to reduce collapse of the airway anddiminishes palate vibration.

In certain examples a mandibular advancement device may comprise anupper splint that is intended to engage with or fit over teeth on theupper jaw or maxilla and a lower splint that is intended to engage withor fit over teeth on the upper jaw or mandible. The upper and lowersplints are connected together laterally via a pair of connecting rods.The pair of connecting rods are fixed symmetrically on the upper splintand on the lower splint.

In such a design the length of the connecting rods is selected such thatwhen the MRD is placed in a patient's mouth the mandible is held in anadvanced position. The length of the connecting rods may be adjusted tochange the level of protrusion of the mandible. A dentist may determinea level of protrusion for the mandible that will determine the length ofthe connecting rods.

Some MRDs are structured to push the mandible forward relative to themaxilla while other MADs, such as the ResMed Narval CC™ MRD are designedto retain the mandible in a forward position. This device also reducesor minimises dental and temporo-mandibular joint (TMJ) side effects.Thus, it is configured to minimises or prevent any movement of one ormore of the teeth.

2.2.3.8 Vent Technologies

Some forms of treatment systems may include a vent to allow the washoutof exhaled carbon dioxide. The vent may allow a flow of gas from aninterior space of a patient interface, e.g., the plenum chamber, to anexterior of the patient interface, e.g., to ambient.

The vent may comprise an orifice and gas may flow through the orifice inuse of the mask. Many such vents are noisy. Others may become blocked inuse and thus provide insufficient washout. Some vents may be disruptiveof the sleep of a bed partner 1100 of the patient 1000, e.g. throughnoise or focussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See International Patent Application Publication No. WO1998/034,665; International Patent Application Publication No. WO2000/078,381; U.S. Pat. No. 6,581,594; US Patent Application PublicationNo. US 2009/0050156; US Patent Application Publication No. 2009/0044808.

TABLE of noise of prior masks (ISO 17510-2: 2007, 10 cmH₂O pressure at 1m) A-weighted A-weighted sound power sound pressure level dB(A) dB(A)Year Mask name Mask type (uncertainty) (uncertainty) (approx.) Glue-on(*) nasal 50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard (*)ResMed nasal 29.5 21.5 1998 Mirage ™ (*) ResMed nasal 36 (3) 28 (3) 2000UltraMirage ™ ResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ™ ResMednasal 30 (3) 22 (3) 2008 Mirage Micro ™ ResMed nasal 29 (3) 22 (3) 2008Mirage ™ SoftGel ResMed nasal 26 (3) 18 (3) 2010 Mirage ™ FX ResMednasal 37   29   2004 Mirage pillows Swift ™ (*) ResMed nasal 28 (3) 20(3) 2005 Mirage pillows Swift ™ II ResMed nasal 25 (3) 17 (3) 2008Mirage pillows Swift ™ LT ResMed nasal 21 (3) 13 (3) 2014 AirFit P10pillows (*) one specimen only, measured using test method specified inISO 3744 in CPAP mode at 10 cmH₂O)

Sound pressure values of a variety of objects are listed below

A-weighted sound Object pressure dB(A) Notes Vacuum cleaner: Nilfisk 68ISO 3744 at 1 m Walter Broadly Litter Hog: B+ distance GradeConversational speech 60 1 m distance Average home 50 Quiet library 40Quiet bedroom at night 30 Background in TV studio 20

2.2.4 Screening, Diagnosis, and Monitoring Systems

Polysomnography (PSG) is a conventional system for diagnosis andmonitoring of cardio-pulmonary disorders, and typically involves expertclinical staff to apply the system. PSG typically involves the placementof 15 to 20 contact sensors on a patient in order to record variousbodily signals such as electroencephalography (EEG), electrocardiography(ECG), electrooculograpy (EOG), electromyography (EMG), etc. PSG forsleep disordered breathing has involved two nights of observation of apatient in a clinic, one night of pure diagnosis and a second night oftitration of treatment parameters by a clinician. PSG is thereforeexpensive and inconvenient. In particular it is unsuitable for homescreening/diagnosis/monitoring of sleep disordered breathing.

Screening and diagnosis generally describe the identification of acondition from its signs and symptoms. Screening typically gives atrue/false result indicating whether or not a patient's SDB is severeenough to warrant further investigation, while diagnosis may result inclinically actionable information. Screening and diagnosis tend to beone-off processes, whereas monitoring the progress of a condition cancontinue indefinitely. Some screening/diagnosis systems are suitableonly for screening/diagnosis, whereas some may also be used formonitoring.

Clinical experts may be able to screen, diagnose, or monitor patientsadequately based on visual observation of PSG signals. However, thereare circumstances where a clinical expert may not be available, or aclinical expert may not be affordable. Different clinical experts maydisagree on a patient's condition. In addition, a given clinical expertmay apply a different standard at different times.

3 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the screening, diagnosis, monitoring, amelioration, treatment,or prevention of respiratory disorders having one or more of improvedcomfort, cost, efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe screening, diagnosis, monitoring, amelioration, treatment orprevention of a respiratory disorder.

Another aspect of the present technology relates to methods used in thescreening, diagnosis, monitoring, amelioration, treatment or preventionof a respiratory disorder.

An aspect of certain forms of the present technology is to providemethods and/or apparatus that improve the compliance of patients withrespiratory therapy.

One form of the present technology comprises a patient interfacecomprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, said plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a first seal-forming structure constructed and arranged to form        a seal with a region of the patient's face surrounding an        entrance to the patient's mouth such that the flow of air at        said therapeutic pressure is delivered to the mouth, the first        seal-forming structure constructed and arranged to maintain said        therapeutic pressure in the plenum chamber throughout the        patient's respiratory cycle in use;    -   a second seal-forming structure constructed and arranged to form        a seal with a region of the patient's face surrounding an        entrance to the patient's nose such that the flow of air at said        therapeutic pressure is delivered to the nose, the second        seal-forming structure constructed and arranged to maintain said        therapeutic pressure in the plenum chamber throughout the        patient's respiratory cycle in use; and    -   a vent structure to allow a continuous flow of gases exhaled by        the patient from an interior of the plenum chamber to vent to        ambient, said vent structure being sized and shaped to maintain        the therapeutic pressure in the plenum chamber in use;    -   the patent interface further comprising:        a pair of support portions provided on opposite sides of the        interface between the second seal forming structure and an        anterior wall of the plenum chamber, wherein the support        portions are configured to oppose compression in the        anterior-posterior direction.

In embodiments:

-   -   a) the support portions are connected to portions of the second        seal forming structure which seal, in use, against the patient's        lip superior;    -   b) the support portions are connected to portions of the second        seal forming structure which, in use, seal to the patient's lip        superior, directly inferior to the lower corners of the        patient's nose;    -   c) the support portions are curved when viewed in cross-section        parallel to a sagittal plane;    -   d) the support portions are curved when viewed in cross-section        parallel to a frontal plane;    -   e) the plenum chamber comprises an oral portion and a nasal        portion;    -   f) each support portion is connected to the oral portion of the        plenum chamber adjacent a boundary of a lateral side wall        portion of the oral portion and a lateral side wall portion of        the nasal portion;    -   g) each support portion is connected to the oral portion of the        shell adjacent a boundary of an anterior wall portion of the        oral portion and an anterior wall portion of the nasal portion;    -   h) the lateral side wall portions of the plenum chamber curve        inwardly adjacent the boundary with the nasal portion, wherein        each support portion is substantially contiguous with an        adjacent lateral side wall portion;    -   i) the second seal-forming structure comprises at least one        nasal aperture configured to deliver a flow of air at said        therapeutic pressure to an entrance to the patient's nares,        wherein, in use no part of either support portion is directly        inferior to the or each nasal aperture;    -   j) the interface further comprises a positioning and stabilising        structure configured to generate a force to hold the        seal-forming structure in a therapeutically effective position        on the patient's head; and/or    -   k) the plenum chamber is at least partially formed by a shell        and the vent structure is provided to the shell.

Another form of the technology comprises a patient interface comprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, said plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a first seal-forming structure connected to an oral portion of        the plenum chamber, the first seal-forming structure constructed        and arranged to form a seal with a region of the patient's face        surrounding an entrance to the patient's mouth such that the        flow of air at said therapeutic pressure is delivered to the        mouth, the first seal-forming structure constructed and arranged        to maintain said therapeutic pressure in the plenum chamber        throughout the patient's respiratory cycle in use;    -   a second seal-forming structure connected to a nasal portion of        the plenum chamber, the second seal-forming structure        constructed and arranged to form a seal with a region of the        patient's face surrounding an entrance to the patient's nose        such that the flow of air at said therapeutic pressure is        delivered to the nose, the second seal-forming structure        constructed and arranged to maintain said therapeutic pressure        in the plenum chamber throughout the patient's respiratory cycle        in use; and    -   a vent structure to allow a continuous flow of gases exhaled by        the patient from an interior of the plenum chamber to vent to        ambient, said vent structure being sized and shaped to maintain        the therapeutic pressure in the plenum chamber in use;    -   wherein    -   a first anterior wall portion of the nasal portion of the plenum        chamber, adjacent a boundary with the oral portion of the plenum        chamber, is more flexible than an immediately adjacent region of        the oral portion of the plenum chamber, and a second anterior        wall portion of the nasal portion of the plenum chamber, which        is immediately adjacent the first anterior wall portion and is        on an opposite side of the first anterior wall portion to the        boundary with the oral portion of the plenum chamber, is less        flexible than the immediately adjacent portions of the anterior        wall.

In examples:

-   -   a) the first anterior wall portion is thinner than the        immediately adjacent portions of the plenum chamber wall;    -   b) the second anterior wall portion is thicker than the        immediately adjacent portions of the plenum chamber wall;    -   c) the first and second anterior wall portions are made from the        same material;    -   d) the first anterior wall portion extends across substantially        an entire width of the nasal portion of the plenum chamber;    -   e) the second anterior wall portion extends across at least a        majority of a width of the nasal portion of the plenum chamber;    -   f) the first anterior wall portion extends in a superior        direction around at least one lateral edge of the second        anterior wall portion;    -   g) the second anterior wall portion extends across substantially        an entire width of the nasal portion of the plenum chamber;    -   h) a central portion of the first anterior wall portion extends        further in the superior direction than lateral portions of the        first anterior wall portion;    -   i) an upper boundary of the first anterior wall portion is        curved;    -   j) a lower boundary of the first anterior wall portion is        curved; and/or    -   k) the plenum chamber is at least partially formed by a shell        and the vent structure is provided to the shell.

Another form of the technology comprises a patient interface comprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, said plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a first seal-forming structure connected to an oral portion of        the plenum chamber, the first seal-forming structure constructed        and arranged to form a seal with a region of the patient's face        surrounding an entrance to the patient's mouth such that the        flow of air at said therapeutic pressure is delivered to the        mouth, the first seal-forming structure constructed and arranged        to maintain said therapeutic pressure in the plenum chamber        throughout the patient's respiratory cycle in use;    -   a second seal-forming structure connected to a nasal portion of        the plenum chamber, the second seal-forming structure        constructed and arranged to form a seal with a region of the        patient's face surrounding an entrance to the patient's nose        such that the flow of air at said therapeutic pressure is        delivered to the nose, the second seal-forming structure        constructed and arranged to maintain said therapeutic pressure        in the plenum chamber throughout the patient's respiratory cycle        in use; and    -   a vent structure to allow a continuous flow of gases exhaled by        the patient from an interior of the plenum chamber to vent to        ambient, said vent structure being sized and shaped to maintain        the therapeutic pressure in the plenum chamber in use;    -   wherein    -   posterior surfaces of the lateral portions of the second seal        forming structure slope in a superior-anterior direction from a        boundary of the first and second seal forming structures.

In examples:

-   -   a) the slope of each lateral portion forms an angle of between        20 degrees and 90 degrees with a mid-contact plane of the mask;    -   b) no part of the patent interface contacts the patient's alar        crest point, in use;    -   c) the interface is configured to prevent occlusion of the        patient's nares, or to at least reduce occlusion relative to the        interfaces of the prior art; and/or    -   d) the plenum chamber is at least partially formed by a shell        and the vent structure is provided to the shell.

Another form of the technology comprises a patient interface comprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, said plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a first seal-forming structure connected to an oral portion of        the plenum chamber, the first seal-forming structure constructed        and arranged to form a seal with a region of the patient's face        surrounding an entrance to the patient's mouth such that the        flow of air at said therapeutic pressure is delivered to the        mouth, the first seal-forming structure constructed and arranged        to maintain said therapeutic pressure in the plenum chamber        throughout the patient's respiratory cycle in use;    -   a second seal-forming structure connected to a nasal portion of        the plenum chamber, the second seal-forming structure        constructed and arranged to form a seal with a region of the        patient's face surrounding an entrance to the patient's nose        such that the flow of air at said therapeutic pressure is        delivered to the nose, the second seal-forming structure        constructed and arranged to maintain said therapeutic pressure        in the plenum chamber throughout the patient's respiratory cycle        in use; and    -   a vent structure to allow a continuous flow of gases exhaled by        the patient from an interior of the plenum chamber to vent to        ambient, said vent structure being sized and shaped to maintain        the therapeutic pressure in the plenum chamber in use;    -   wherein    -   a boundary between the first seal-forming structure and the        second seal-forming structure comprises a ridge.

In examples:

-   -   a) the ridge has a radius of curvature of less than 2 mm;    -   b) the ridge extends across substantially an entire boundary        between the first seal forming structure and the second seal        forming structure;    -   c) in use, the ridge engages a patient's face proximate the        entrances to the nares where the ala meets the face above the        lip superior;    -   d) the ridge resists creases forming in the first and/or second        seal forming structure adjacent the ridge; and/or    -   e) in use the plenum chamber is at least partially formed by a        shell and the vent structure is provided to the shell.

Another form of the technology comprises a patient interface comprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, said plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a first seal-forming structure connected to an oral portion of        the plenum chamber, the first seal-forming structure constructed        and arranged to form a seal with a region of the patient's face        surrounding an entrance to the patient's mouth such that the        flow of air at said therapeutic pressure is delivered to the        mouth, the first seal-forming structure constructed and arranged        to maintain said therapeutic pressure in the plenum chamber        throughout the patient's respiratory cycle in use;    -   a second seal-forming structure connected to a nasal portion of        the plenum chamber, the second seal-forming structure        constructed and arranged to form a seal with a region of the        patient's face surrounding an entrance to the patient's nose        such that the flow of air at said therapeutic pressure is        delivered to the nose, the second seal-forming structure        constructed and arranged to maintain said therapeutic pressure        in the plenum chamber throughout the patient's respiratory cycle        in use; and    -   a vent structure to allow a continuous flow of gases exhaled by        the patient from an interior of the plenum chamber to vent to        ambient, said vent structure being sized and shaped to maintain        the therapeutic pressure in the plenum chamber in use;    -   wherein,    -   at least a portion of the oral portion of plenum chamber        comprises a flexible shell, wherein the flexible shell is formed        from a material having a Young's modulus of less than 0.4 GPa.

In examples:

-   -   a) the flexible shell is formed from a material having a Young's        modulus less than 0.1 GPa, preferably between 0.3-0.7 MPa.    -   b) at least one component is connected to the flexible shell,        wherein the at least one component is stiffer than a portion of        the flexible shell adjacent the component;    -   c) the at least one component comprises one or more of: a vent        module; a headgear connector; a headgear connector connected to        a rigidizing arm; a rigidizing member; a less flexible shell        portion;    -   d) the at least one component is releasably connectable to the        flexible shell;    -   e) the at least one component is permanently connected to the        flexible shell;    -   f) the at least one component is overmoulded to the flexible        shell;    -   g) the flexible shell comprises stiffening portions having        greater thickness than immediately adjacent portions of the        flexible shell;    -   h) the at least one component is configured as stiffening ribs        or bands;    -   i) a central portion of the oral portion of the plenum chamber        has a greater stiffness than the remainder of the plenum        chamber; and/or    -   j) the plenum chamber is at least partially formed by a shell        and the vent structure is provided to the shell.

Another form of the present technology comprises a patient interfacecomprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH₂O above ambient air pressure, the plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a seal-forming structure constructed and arranged to form a seal        with a region of the patient's face surrounding an entrance to        the patient's airways for sealed delivery of a flow of        pressurized air at the therapeutic pressure of at least 6 cmH₂O        above ambient air pressure throughout the patient's respiratory        cycle in use, the seal-forming structure comprises:        -   a first section constructed from a first material, the first            section configured to sealingly engage against a first            region of the patient's face, and        -   a second section constructed from a second material            different than the first material, the second section            configured to sealingly engage against a second region of            the patient's face, wherein the second material is foam, and    -   a positioning and stabilising structure to provide a force to        hold a seal-forming structure in a therapeutically effective        position on a patient's head.

In examples:

-   -   a) the first material is silicone;    -   b) the first section is flush with the second section at the        transition;    -   c) the plenum chamber includes a mounting surface, the second        section of the seal-forming structure coupled to the mounting        surface;    -   d) the mounting surface is substantially flat and substantially        perpendicular to an anterior-posterior direction of the        patient's head, in use;    -   e) the mounting surface is constructed from the first material;    -   f) the first section extends beyond the mounting surface, and        forms an overhang relative to the mounting surface;    -   g) the overhang is configured to contact the patient proximate        each nasal ala;    -   h) the plenum chamber inlet port is formed anterior to the        mounting surface, in use, and wherein the second material does        not contact the plenum chamber inlet port;    -   i) the mounting surface is substantially U-shaped or C-shaped        and includes a first free end and a second free end, and        wherein, in use, the first free end is configured to be spaced        apart from the second free end along the patient's lip superior        so as to leave the patient's philtrum uncovered by the mounting        surface;    -   j) the first section and the plenum chamber are integrally        formed as a one-piece construction during a molding process;    -   k) the plenum chamber is at least partially constructed from the        first material;    -   l) the second section is coupled to the plenum chamber with an        adhesive;    -   m) the second section includes a varying thickness;    -   n) the second section includes a first thickness and a second        thickness greater than the first thickness, wherein the first        thickness is adjacent to the second thickness;    -   o) the seal-forming structure is configured to form a seal        against the patient's face, wherein first section and the second        section each combine to form a portion of the seal;    -   p) the seal-forming structure is a nasal cushion or a nasal        cradle;    -   q) the second section is configured to a nasal alar region of        the patient, in use;    -   r) the seal-forming structure is an oronasal cushion, an        ultra-compact full face mask, or a full-face mask;    -   s) the first section is configured to contact the patient's        nose, in use, between at least the patient's pronasale and the        patient's subnasale, and between at least each of the patient's        nasal ala;    -   t) the second section is configured to contact around the        patient's mouth, in use, between at least the patient's lip        superior and the patient's lip inferior, and outside of the        patient's mouth width adjacent at least each of the patient's        nasal ala;    -   u) a bridge portion of the second section is configured to        contact the patient's lip superior in use;    -   v) at least a portion of the bridge portion is unbacked, and is        configured to move into the plenum chamber when contacted by the        patient's lip superior;    -   w) the transition is between the bridge portion and the first        section;    -   x) the seal-forming structure is configured to not seal against        the patient's philtrum;    -   y) a portion of the second section is configured to seal against        a region inferior to the patient's nares and proximate to the        patient's nasal ala;    -   z) the first section is thinner than the second section;    -   aa) when viewed in cross-section, the second section has a        substantially rectangular profile;    -   bb) the second section includes a substantially squared edge        configured to contact the patient in use;    -   cc) the substantially squared edge is configured to contact the        proximate the nasal ala at a juncture of the patient's corner of        nose region and the patient's lip superior; and/or    -   dd) the first section is configured to receive a first component        of the force and the second section is configured to receive a        second component of the force, wherein the first section and the        second section are configured to apply the same sealing force to        the patient when the first component is less than the second        component.

Another aspect of the present technology comprises a patient interfacecomprising:

-   -   a plenum chamber formed from a first material and pressurisable        to a therapeutic pressure of at least 6 cmH2O above ambient air        pressure, the plenum chamber including a plenum chamber inlet        port sized and structured to receive a flow of air at the        therapeutic pressure for breathing by a patient, the plenum        chamber including a mounting surface;    -   a seal-forming structure constructed and arranged to form a seal        with a region of the patient's face surrounding an entrance to        the patient's airways for sealed delivery of a flow of        pressurized air at the therapeutic pressure of at least 6 cmH2O        above ambient air pressure throughout the patient's respiratory        cycle in use, the seal-forming structure comprises:    -   a first section constructed from the first material, the first        section configured to sealingly engage against a first region of        the patient's face, and    -   a second section constructed from a second material different        than the first material, the second section connected to the        mounting surface, the second section configured to sealingly        engage against a second region of the patient's face, and    -   a positioning and stabilising structure to provide a force to        hold a seal-forming structure in a therapeutically effective        position on a patient's head;    -   wherein the mounting surface is recessed relative to the first        section by a first distance; and    -   wherein the second section includes a thickness substantially        equal to the first distance so that the first section and the        second section are substantially flush with one another.

In examples:

-   -   a) the second material is foam;    -   b) the first material is silicone;    -   c) the seal-forming structure is an oronasal cushion, an        ultra-compact full face mask, or a full-face mask;    -   d) the mounting surface is substantially flat and substantially        perpendicular to an anterior-posterior direction of the        patient's head, in use;    -   e) the first section extends beyond the mounting surface, and        forms an overhang relative to the mounting surface;    -   f) the overhang is configured to contact the patient proximate        each nasal ala; and/or    -   g) the mounting surface is substantially U-shaped or C-shaped        and includes a first free end and a second free end, and        wherein, in use, the first free end is configured to be spaced        apart from the second free end along the patient's lip superior        so as to leave the patient's philtrum uncovered by the mounting        surface.

Another aspect of the present technology comprises a patient interfacecomprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH2O above ambient air pressure, the plenum chamber        including:        -   a plenum chamber inlet port sized and structured to receive            a flow of air at the therapeutic pressure for breathing by a            patient, the plenum chamber inlet port having at least one            substantially straight side,        -   a mounting surface being inclined relative to the            substantially straight surface;    -   a seal-forming structure constructed and arranged to form a seal        with a region of the patient's face surrounding an entrance to        the patient's airways for sealed delivery of a flow of        pressurized air at the therapeutic pressure of at least 6 cmH2O        above ambient air pressure throughout the patient's respiratory        cycle in use, the seal-forming structure comprises:    -   a first section constructed from the first material, the first        section configured to sealingly engage against a first region of        the patient's face, and    -   a second section constructed from a second material different        than the first material, the second section connected to the        mounting surface, the second section configured to sealingly        engage against a second region of the patient's face, and    -   a positioning and stabilising structure to provide a force to        hold a seal-forming structure in a therapeutically effective        position on a patient's head;    -   wherein the straight surface is configured to be positioned        substantially parallel to the patient's sagittal plane in use;        and    -   wherein the positioning and stabilising structure is configured        to provide a greater force to the second section as a result of        the position of the straight surface in use.

In examples:

-   -   a) the second material is foam;    -   b) the first material is silicone;    -   c) the plenum chamber inlet port is a first plenum chamber inlet        port, wherein the plenum chamber further includes a second        plenum chamber inlet port;    -   d) the first section extends beyond the mounting surface, and        forms an overhang relative to the mounting surface;    -   e) the overhang is configured to contact the patient proximate        each nasal ala;    -   f) the mounting surface is substantially U-shaped or C-shaped        and includes a first free end and a second free end, and        wherein, in use, the first free end is configured to be spaced        apart from the second free end along the patient's lip superior        so as to leave the patient's philtrum uncovered by the mounting        surface;    -   g) the second section is permanently connected to the mounting        surface;    -   h) the second section is removably connected to the mounting        surface;    -   i) the second section is configured to contact the second region        at the patient's lip superior; and/or    -   j) the first section is configured to contact the first region        at the patient's alar rim.

Another aspect of the present technology comprises a seal-formingstructure constructed and arranged to form a seal with a region of thepatient's face surrounding an entrance to the patient's airways forsealed delivery of a flow of pressurized air at the therapeutic pressureof at least 6 cmH2O above ambient air pressure throughout the patient'srespiratory cycle in use, the seal-forming structure comprises:

-   -   a first section constructed from a first material, the first        section configured to sealingly engage against a first region of        the patient's face; and    -   a second section constructed from a second material different        than the first material, the second section configured to        sealingly engage against a second region of the patient's face,        wherein the second material is foam.

Another aspect of the present technology comprises a patient interfacecomprising:

-   -   a plenum chamber pressurisable to a therapeutic pressure of at        least 6 cmH2O above ambient air pressure, the plenum chamber        including a plenum chamber inlet port sized and structured to        receive a flow of air at the therapeutic pressure for breathing        by a patient;    -   a seal-forming structure constructed and arranged to form a seal        with a region of the patient's face surrounding an entrance to        the patient's airways for sealed delivery of a flow of        pressurized air at the therapeutic pressure of at least 6 cmH2O        above ambient air pressure throughout the patient's respiratory        cycle in use; and a positioning and stabilising structure to        provide a force to hold a seal-forming structure in a        therapeutically effective position on a patient's head.

In some forms, a) a first second is constructed from a first materialand a second section is constructed from a second material differentthat the first material; b) the first material is configured to contactthe patients face; c) the second material is configured to contact thepatient's face; d) the first material is silicone; and/or e) the secondmaterial is foam.

Another aspect of one form of the present technology is an oro-nasalpatient interface that is more compact and less obtrusive to thepatient.

Another aspect of one form of the present technology is an oro-nasalpatient interface that has a nasal cushion portion that provides animproved fit to the lower corners of the nose.

Another aspect of one form of the present technology is an oro-nasalpatient interface that reduces occlusive contact on the nose.

Another aspect of one form of the present technology is an oro-nasalpatient interface that can self adjust to accommodate patients with awide variety of nasolabial angles.

Another aspect of one form of the present technology is an oro-nasalpatient interface that has a relatively flexible shell.

Another aspect of one form of the present technology is a patientinterface that is moulded or otherwise constructed with a perimetershape which is complementary to that of an intended wearer.

An aspect of one form of the present technology is a method ofmanufacturing apparatus.

An aspect of certain forms of the present technology is a medical devicethat is easy to use, e.g. by a person who does not have medicaltraining, by a person who has limited dexterity, vision or by a personwith limited experience in using this type of medical device.

An aspect of one form of the present technology is a portable RPT devicethat may be carried by a person, e.g., around the home of the person.

An aspect of one form of the present technology is a patient interfacethat may be washed in a home of a patient, e.g., in soapy water, withoutrequiring specialised cleaning equipment. An aspect of one form of thepresent technology is a humidifier tank that may be washed in a home ofa patient, e.g., in soapy water, without requiring specialised cleaningequipment.

The methods, systems, devices and apparatus described may be implementedso as to improve the functionality of a processor, such as a processorof a specific purpose computer, respiratory monitor and/or a respiratorytherapy apparatus. Moreover, the described methods, systems, devices andapparatus can provide improvements in the technological field ofautomated management, monitoring and/or treatment of respiratoryconditions, including, for example, sleep disordered breathing.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

4 BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

4.1 Respiratory Therapy Systems

FIG. 1A shows a system including a patient 1000 wearing a patientinterface 3000, in the form of nasal pillows, receiving a supply of airat positive pressure from an RPT device 4000. Air from the RPT device4000 is conditioned in a humidifier 5000, and passes along an aircircuit 4170 to the patient 1000. A bed partner 1100 is also shown. Thepatient is sleeping in a supine sleeping position.

FIG. 1B shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal mask, receiving a supply of airat positive pressure from an RPT device 4000. Air from the RPT device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1C shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a full-face mask, receiving a supply ofair at positive pressure from an RPT device 4000. Air from the RPTdevice is humidified in a humidifier 5000, and passes along an aircircuit 4170 to the patient 1000. The patient is sleeping in a sidesleeping position.

4.2 Respiratory System and Facial Anatomy

FIG. 2A shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2B shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

FIG. 2C is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermilion, lowervermilion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion. Also indicated are the directionssuperior, inferior, radially inward and radially outward.

FIG. 2D is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, alar crest point,otobasion superior and otobasion inferior. Also indicated are thedirections superior & inferior, and anterior & posterior.

FIG. 2E is a further side view of a head. The approximate locations ofthe Frankfort horizontal and nasolabial angle are indicated. The coronalplane is also indicated.

FIG. 2F shows a base view of a nose with several features identifiedincluding naso-labial sulcus, lip inferior, upper Vermilion, naris,subnasale, columella, pronasale, the major axis of a naris and themidsagittal plane.

FIG. 2G shows a side view of the superficial features of a nose.

FIG. 2H shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue,frontal process of the maxilla and fibrofatty tissue.

FIG. 2I shows a medial dissection of a nose, approximately severalmillimeters from the midsagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage.

FIG. 2J shows a front view of the bones of a skull including thefrontal, nasal and zygomatic bones. Nasal concha are indicated, as arethe maxilla, and mandible.

FIG. 2K shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter, sternocleidomastoidand trapezius.

FIG. 2L shows an anterolateral view of a nose.

4.3 Patient Interface

FIG. 3A shows a patient interface in the form of a nasal mask inaccordance with one form of the present technology.

FIG. 3B shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3C.

FIG. 3C shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a positive sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3B.

FIG. 3D shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a value of zero.

FIG. 3E shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively small magnitude whencompared to the magnitude of the curvature shown in FIG. 3F.

FIG. 3F shows a schematic of a cross-section through a structure at apoint. An outward normal at the point is indicated. The curvature at thepoint has a negative sign, and a relatively large magnitude whencompared to the magnitude of the curvature shown in FIG. 3E.

FIG. 3G shows a cushion for a mask that includes two pillows. Anexterior surface of the cushion is indicated. An edge of the surface isindicated. Dome and saddle regions are indicated.

FIG. 3H shows a cushion for a mask. An exterior surface of the cushionis indicated. An edge of the surface is indicated. A path on the surfacebetween points A and B is indicated. A straight line distance between Aand B is indicated. Two saddle regions and a dome region are indicated.

FIG. 3I shows the surface of a structure, with a one dimensional hole inthe surface. The illustrated plane curve forms the boundary of a onedimensional hole.

FIG. 3J shows a cross-section through the structure of FIG. 3I. Theillustrated surface bounds a two dimensional hole in the structure ofFIG. 3I.

FIG. 3K shows a perspective view of the structure of FIG. 3I, includingthe two dimensional hole and the one dimensional hole. Also shown is thesurface that bounds a two dimensional hole in the structure of FIG. 3I.

FIG. 3L shows a mask having an inflatable bladder as a cushion.

FIG. 3M shows a cross-section through the mask of FIG. 3L, and shows theinterior surface of the bladder. The interior surface bounds the twodimensional hole in the mask.

FIG. 3N shows a further cross-section through the mask of FIG. 3L. Theinterior surface is also indicated.

FIG. 3O illustrates a left-hand rule.

FIG. 3P illustrates a right-hand rule.

FIG. 3Q shows a left ear, including the left ear helix.

FIG. 3R shows a right ear, including the right ear helix.

FIG. 3S shows a right-hand helix.

FIG. 3T shows a view of a mask, including the sign of the torsion of thespace curve defined by the edge of the sealing membrane in differentregions of the mask.

FIG. 3U shows a view of a plenum chamber 3200 showing a sagittal planeand a mid-contact plane.

FIG. 3V shows a view of a posterior of the plenum chamber of FIG. 3U.The direction of the view is normal to the mid-contact plane. Thesagittal plane in FIG. 3V bisects the plenum chamber into left-hand andright-hand sides.

FIG. 3W shows a cross-section through the plenum chamber of FIG. 3V, thecross-section being taken at the sagittal plane shown in FIG. 3V. A‘mid-contact’ plane is shown. The mid-contact plane is perpendicular tothe sagittal plane. The orientation of the mid-contact plane correspondsto the orientation of a chord 3210 which lies on the sagittal plane andjust touches the cushion of the plenum chamber at two points on thesagittal plane: a superior point 3220 and an inferior point 3230.Depending on the geometry of the cushion in this region, the mid-contactplane may be a tangent at both the superior and inferior points. Fororo-nasal interfaces configured with plenum chambers having separateoral and nasal portions, for example Ultra Compact Full Face (UCFF)masks, the superior point and inferior points are on the seal formingstructure of the oral portion of the mask.

FIG. 3X shows the plenum chamber 3200 of FIG. 3U in position for use ona face. The sagittal plane of the plenum chamber 3200 generallycoincides with the midsagittal plane of the face when the plenum chamberis in position for use. The mid-contact plane corresponds generally tothe ‘plane of the face’ when the plenum chamber is in position for use.In FIG. 3X the plenum chamber 3200 is that of a nasal mask, and thesuperior point 3220 sits approximately on the sellion, while theinferior point 3230 sits on the lip superior.

4.4 RPT Device

FIG. 4A shows an RPT device in accordance with one form of the presenttechnology.

FIG. 4B is a schematic diagram of the pneumatic path of an RPT device inaccordance with one form of the present technology. The directions ofupstream and downstream are indicated with reference to the blower andthe patient interface. The blower is defined to be upstream of thepatient interface and the patient interface is defined to be downstreamof the blower, regardless of the actual flow direction at any particularmoment. Items which are located within the pneumatic path between theblower and the patient interface are downstream of the blower andupstream of the patient interface.

4.5 Humidifier

FIG. 5A shows an isometric view of a humidifier in accordance with oneform of the present technology.

FIG. 5B shows an isometric view of a humidifier in accordance with oneform of the present technology, showing a humidifier reservoir 5110removed from the humidifier reservoir dock 5130.

4.6 Breathing Waveforms

FIG. 6 shows a model typical breath waveform of a person while sleeping.

4.7 Patient Interface Examples of the Present Technology

FIG. 7 is a rear perspective view of a plenum chamber in accordance withone form of the present technology, with inlet ports not shown.

FIG. 8 is a rear view of the plenum chamber of FIG. 7 .

FIG. 9 is a front view of the plenum chamber of FIG. 7 .

FIG. 10 is a side view of the plenum chamber of FIG. 7 .

FIG. 11 is a top view of the plenum chamber of FIG. 7 .

FIG. 12 is a cross-section of the plenum chamber through plane 12-12.

FIG. 13 is a bottom view of the plenum chamber of FIG. 7 .

FIG. 14 is a cross-section of the plenum chamber through plane 14-14.

FIG. 15 is a cross-section of the plenum chamber through plane 15-15.

FIG. 16 is a cross-section of the plenum chamber through plane 16-16.

FIG. 16-1 is a cross-section of the plenum chamber through plane16-1-16-1.

FIG. 16-2 is a cross-section of the plenum chamber of FIG. 16-1 ,illustrating the plenum chamber in a deformed position.

FIG. 17 is a cross-section of the plenum chamber through plane 17-17.

FIG. 18 is a cross-section of the plenum chamber through plane 18-18.

FIG. 18-1 is a cross-section of the plenum chamber through plane18-1-18-1.

FIG. 18-2 is a cross-section of the plenum chamber through plane18-2-18-2.

FIG. 19 shows a side view of the plenum chamber in an in-use position ona patient's face, with the plenum chamber shown in outline for clarity.

FIG. 20 shows a patient's face with particular areas of engagement by aseal forming structure indicated.

FIG. 21 is a front perspective view of a patient interface in accordancewith another form of the technology.

FIG. 21-1 is a front perspective view of a patient interface inaccordance with another form of the technology.

FIG. 22 is a front perspective view of a patient interface in accordancewith yet another form of the technology, with a vent removed.

FIG. 23 is a front perspective view of a patient interface having aframe for connecting headgear straps to the plenum chamber.

FIG. 24 is an exploded view of the patient interface of FIG. 23 .

FIG. 25 is a front view of a frame and plenum chamber in accordance withone form of the technology.

FIG. 26 is a front view of a frame and plenum chamber in accordance withanother form of the technology.

FIG. 27 is a rear view of the frame of FIG. 26 , illustrating a taperedopening.

FIG. 28 is a front view of a frame and plenum chamber in accordance withyet another form of the technology.

FIG. 29 is a rear view of a patient interface having a foam insert.

FIG. 30 is a rear perspective view of the patient interface of FIG. 29 .

FIG. 30A is a cross-section of the patient interface of FIG. 30 throughplane 30A-30A.

FIG. 31 is a side view of the patient interface of FIG. 29 .

FIG. 31A is a cross-section of the patient interface of FIG. 31 throughplane 31A-31A.

FIG. 32 is a rear view of a patient interface having a foam insert inaccordance with another form of the technology.

FIG. 33 is a side view of the patient interface of FIG. 32 .

FIG. 34 is a rear perspective view of a plenum chamber including amounting flange for mounting a foam material. The plenum chamber usableas a full face mask.

FIG. 35 is a side view of the plenum chamber of FIG. 34 .

FIG. 36 is a rear perspective view of a plenum chamber including amounting flange for mounting a foam material. The plenum chamber usableas a nasal only mask.

FIG. 37 is a rear perspective view of a patient interface including foammaterial coupled to the plenum chamber of FIG. 36 .

FIG. 38 is a side view of the patient interface of FIG. 37 .

5 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

The following description is provided in relation to various exampleswhich may share one or more common characteristics and/or features. Itis to be understood that one or more features of any one example may becombinable with one or more features of another example or otherexamples. In addition, any single feature or combination of features inany of the examples may constitute a further example.

Where anatomical directional terms are used in describing aspects andexamples of the present technology, such as “anterior”, “posterior”,“superior” and the like, the directions are to be read in the context ofthe present technology during use by the patient. For example, ananterior side of a patient interface refers to the side of the patientinterface which is anterior with respect to the patient when the patienthas donned the interface in the intended manner.

Where surfaces or portions are described as facing a direction, e.g.“superior facing”, “anterior facing” and the like, unless the contextclearly requires otherwise, the surfaces or portions are to beunderstood as at least partially facing in the particular direction. Aportion may be “superior facing” if the portion generally faces asuperior direction, even if it also partially faces another direction.

5.1 Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising applying positive pressure to theentrance of the airways of a patient 1000.

In certain examples of the present technology, a supply of air atpositive pressure is provided to the nasal passages of the patient viaone or both nares.

In certain examples of the present technology, mouth breathing islimited, restricted or prevented.

5.2 Respiratory Therapy Systems

In one form, the present technology comprises a respiratory therapysystem for treating a respiratory disorder. The respiratory therapysystem may comprise an RPT device 4000 for supplying a flow of air tothe patient 1000 via an air circuit 4170 and a patient interface 3000.

5.3 Patient Interface

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure 3300, a vent 3400, one form of connection port3600 for connection to air circuit 4170, and a forehead support 3700. Insome forms a functional aspect may be provided by one or more physicalcomponents. In some forms, one physical component may provide one ormore functional aspects. In use the seal-forming structure 3100 isarranged to surround an entrance to the airways of the patient so as tomaintain positive pressure at the entrance(s) to the airways of thepatient 1000. The sealed patient interface 3000 is therefore suitablefor delivery of positive pressure therapy.

In some examples of the present technology, the plenum chamber is atleast partially formed by a shell 3250. In examples the shell 3250 or aportion of the shell 3250 may be somewhat flexible, as is discussedfurther below.

The patient interface in some examples of the technology is an oro-nasalpatient interface, that is, the patient interface is configured to sealaround both the patient's nasal airways and oral airway. In someexamples the patient interface comprises separate seals around the eachof the nasal airways and the oral airway.

In the examples shown in FIGS. 7-22 the seal forming structure at thenasal portion does not lie over a nose bridge region or nose ridgeregion of the patient's face and instead seals against inferior surfacesof the patient's nose.

If a patient interface is unable to comfortably deliver a minimum levelof positive pressure to the airways, the patient interface may beunsuitable for respiratory pressure therapy.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 6 cmH₂O with respect to ambient.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 10 cmH₂O with respect to ambient.

The patient interface 3000 in accordance with one form of the presenttechnology is constructed and arranged to be able to provide a supply ofair at a positive pressure of at least 20 cmH₂O with respect to ambient.

5.3.1 Seal-Forming Structure

In one form of the present technology, a seal-forming structure 3100provides a target seal-forming region, and may additionally provide acushioning function. The target seal-forming region is a region on theseal-forming structure 3100 where sealing may occur. The region wheresealing actually occurs—the actual sealing surface—may change within agiven treatment session, from day to day, and from patient to patient,depending on a range of factors including for example, where the patientinterface was placed on the face, tension in the positioning andstabilising structure and the shape of a patient's face.

As is described in greater detail below, in certain forms of theinvention the seal forming structure 3100 comprises a first seal formingstructure 3101 connected to an oral portion 3201 of the plenum chamberand constructed and arranged to form seal with a region of the patient'sface surrounding an entrance to the patient's mouth, and a secondseal-forming structure 3102 connected to a nasal portion 3202 of theplenum chamber 3200 constructed and arranged to form a seal with aregion of the patient's face surrounding an entrance to the patient'snose. The phrase “connected to” is used herein to refer to portions orcomponents which are formed as a single piece as well as to portions orcomponents which are formed separately and subsequently joined together.In some cases components may be connected by an intermediate component.

In certain forms, the first seal forming structure 3101 sealsindependently against the patient's face than the second seal formingstructure 3102.

In certain forms, the first seal forming structure 3101 and the secondseal forming structure 3102 cooperate to form a single common sealagainst the patient's face.

In one form the target seal-forming region is located on an outsidesurface of the seal-forming structure 3100.

In certain forms of the present technology, the seal-forming structure3100 is constructed from a biocompatible material, e.g. silicone rubber.

A seal-forming structure 3100 in accordance with the present technologymay be constructed from a soft, flexible, resilient material such assilicone.

In certain forms of the present technology, a system is providedcomprising more than one seal-forming structure 3100, each beingconfigured to correspond to a different size and/or shape range. Forexample the system may comprise one form of a seal-forming structure3100 suitable for a large sized head, but not a small sized head andanother suitable for a small sized head, but not a large sized head.

5.3.1.1 Sealing Mechanisms

In one form, the seal-forming structure 3100 includes a sealing flangeutilizing a pressure assisted sealing mechanism. In use, the sealingflange can readily respond to a system positive pressure in the interiorof the plenum chamber 3200 acting on its underside to urge it into tightsealing engagement with the face. The pressure assisted mechanism mayact in conjunction with elastic tension in the positioning andstabilising structure.

In one form, the seal-forming structure 3100 comprises a sealing flangeand a support flange. The sealing flange comprises a relatively thinmember with a thickness of less than about 1 mm, for example about 0.25mm to about 0.45 mm, which extends around the perimeter of the plenumchamber 3200. Support flange may be relatively thicker than the sealingflange. The support flange is disposed between the sealing flange andthe marginal edge of the plenum chamber 3200, and extends at least partof the way around the perimeter. The support flange is or includes aspring-like element and functions to support the sealing flange frombuckling in use. Limiting the occurrences of buckling may limit creasesfrom forming in the seal-forming structure 3100, which may lead to leaksand loss of the therapeutic pressure.

In one form, the seal-forming structure 3100 may comprise a compressionsealing portion or a gasket sealing portion. In use the compressionsealing portion, or the gasket sealing portion is constructed andarranged to be in compression, e.g. as a result of elastic tension inthe positioning and stabilising structure.

In one form, the seal-forming structure 3100 comprises a tensionportion. In use, the tension portion is held in tension, e.g. byadjacent regions of the sealing flange.

In one form, the seal-forming structure 3100 comprises a region having atacky or adhesive surface.

In certain forms of the present technology, a seal-forming structure3100 may comprise one or more of a pressure-assisted sealing flange, acompression sealing portion, a gasket sealing portion, a tensionportion, and a portion having a tacky or adhesive surface.

5.3.1.2 Nasal Region

Referring next to FIGS. 7 to 18 , in certain forms of the presenttechnology, the second seal forming structure 3102 comprises a centralportion 3110 configured to seal to surfaces of the patient's nose inuse. The central portion may seal to an inferior periphery of thepatient's nose (e.g. surrounding the patient's nares) and to thepatient's lip superior. In examples a portion of the seal formingstructure may engage the patient's septum. The second seal formingstructure 3102 may further comprise lateral portions 3111 on lateralsides of the central portion 3110. In examples, the seal formingstructure 3102 may be configured to contact the patient's face below thebridge of the nose or below the pronasale.

As best seen in FIGS. 10 and 16-19 , posterior surfaces 3112 of thelateral portions 3111 slope forward in a superior/anterior directionfrom the boundary 3103 of the first and second seal forming structures3101, 3102 such that in profile the posterior side of the nasal part ofthe mask slopes forward.

In embodiments provided with a ridge 3120 (as described further below),the posterior surfaces 3112 of the lateral portions 3111 may slopeforward from the ridge 3120.

In some forms of the technology the posterior surfaces 3112 of thelateral portions 3111 form an angle with a mid-contact plane of the maskof between 20° and 90°. The mid-contact plane may be perpendicular tothe sagittal plane, and may extend substantially along a length of theridge 3120 and the chord 3210.

As shown in FIG. 19 , in some embodiments the lateral portions 3111 areconfigured such that no part of the patient interface 3000 contacts thepatient's alar crest point 1020 when in use.

Configuring the lateral portions 3111 to slope in this way results in asmaller portion of the nasal part of the interface 3000 extending overthe sides of the ala than some similar interfaces of the prior art. Insome forms of the technology this results in the portion of the alawhich is in contact with the seal-forming structure 3100 being reducedrelative to interfaces with lateral portions which slope backward,toward the patient's face, thereby reducing the proportion of the alawhich can be deformed and occluded by the seal-forming structure 3100,for example when the patient sleeps on their side with the interface incontact with a pillow.

5.3.1.3 Boundary of Oral and Nasal Regions

With particular reference to FIGS. 7, 8 and 16-18 , in one form of thetechnology the boundary between the first sealing forming structure 3101and the second seal forming structure 3102 forms or comprises a corneror ridge 3120. In use, the corner or ridge 3120 may engage the patient'sface above the lip superior and immediately below the nose.

In embodiments the corner or ridge 3120 forms a sharper angle than theequivalent portion or area of some oro-nasal masks of the prior art, forexample those described in PCT application No. PCT/AU2019/050278.

The sharper angle reduces the likelihood of creases forming in the firstand/or second seal forming structures 3101, 3102 on or adjacent thecorner or ridge 3120 when the mask is donned and therapy is applied.Some oro-nasal patient interfaces which do not use such a structure mayrequire a very thin, rounded formation in this area which may be lessresistant to creasing. By contrast, the corner or ridge 3120 may bestiffer, and may hold its shape better, than such interfaces and maytherefore seal better against the concavities and creases present aroundthe patient's nose. This effect may be enhanced in embodiments which areprovided with support portions, for example support portions 3260 asdescribed herein, which resist or oppose compression of this region.

In some forms of the technology the radius of the corner or ridge 3120may be less than 2 mm, for example around 1.75 mm. In one form of thetechnology the radius may vary from approximately 1.75 mm in the centreof the ridge to approximately 0.75 mm at the lateral portions.

The angle formed by the first and second sealing structures may bebetween 20 degrees and 90 degrees, for example 36 degrees.

In some forms of the technology, the corner or ridge 3120 may extendacross substantially an entire boundary 3103 between the first sealforming structure 3101 and the second seal forming structure 3102. Inembodiments the corner or ridge 3120 may engage the patient's face atleast approximate the entrances to the nares, for example where the alameets the face above the lip superior, as indicated by areas 1010 inFIG. 20 .

5.3.1.4 Oral Region

As is described above, in one form the non-invasive patient interface3000 comprises a first seal-forming structure 3101 that forms a seal inuse around the patient's mouth. The first seal forming structure 3101may form a seal on a chin-region of the patient's face.

In one form, the seal-forming structure includes a saddle-shaped regionconstructed to form a seal in use on a chin-region of the patient'sface.

The seal forming structure 3100 comprises a lip inferior portion 3130which forms a seal against the chin region of the patient and/or the lipinferior and/or supramenton of the patient. The lip inferior portion3130 may be connected to (e.g. contiguous with) a lip superior portion3131 via an oral hole peripheral portion 3132, as shown in FIG. 16 .

The seal forming structure 3100 comprises a relatively low wallthickness (compared to other portions of the interface), for exampleless than 0.7 mm, at the oral hole peripheral portion 3132, the lipinferior portion 3130 of the seal forming structure which lies againstthe chin region, and at least the centre of the lip inferior portion3130. The low wall thickness in these locations assists in achieving aneffective, comfortable seal. The seal forming structure in these regionsis able to readily conform to any complex geometry.

In some forms of the technology the oral hole 3133 is substantiallytrapezoidal rather than oval or elliptical, in order to more accuratelycorrespond to a shape of the patient's nose. This shape of oral hole mayallow the interface 3000 to be particularly compact, and not besubstantially wider than a width of the patient's nares.

5.3.1.5 Nasal Pillows

In one form the seal-forming structure of the non-invasive patientinterface 3000 comprises a pair of nasal puffs, or nasal pillows, eachnasal puff or nasal pillow being constructed and arranged to form a sealwith a respective naris of the nose of a patient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose, a stalk, a flexible region on theunderside of the frusto-cone and connecting the frusto-cone to thestalk. In addition, the structure to which the nasal pillow of thepresent technology is connected includes a flexible region adjacent thebase of the stalk. The flexible regions can act in concert to facilitatea universal joint structure that is accommodating of relative movementboth displacement and angular of the frusto-cone and the structure towhich the nasal pillow is connected. For example, the frusto-cone may beaxially displaced towards the structure to which the stalk is connected.

5.3.1.6 Foam Sealing Portion

As shown in FIGS. 29-40 , some forms of the patient interface 3000 areconstructed from multiple materials that together form a cavity 3272,which receives the flow of pressurized air, and air exhaled by thepatient.

In some forms, the seal-forming structure 3100 is constructed from afirst material 3150 and a second material 3152, which includes at leastone material property that is different than in the first material 3150.The first and second materials 3150, 3152 cooperate in order to form aseal. Each of the first and second materials 3150, 3152 are able to sealagainst the patient's face and limit leaking of the pressurized air fromthe cavity 3272.

In some forms, the seal-forming structure 3100 is constructed entirelyfrom the second material 3152, and a plenum chamber 3200 (describedbelow) is constructed from the first material 3150. The first material3150 may not contact the patient.

In some forms, the seal-forming structure 3100 may include a separateseal for sealing around the patient's nares, and for sealing around thepatient's mouth. Each separate seal may be constructed from a differentmaterial (e.g., one is constructed from the first material 3150, and theother is constructed from the second material 3152).

In some forms, the seal-forming structure 3100 may be constructed fromboth the first material 3150 and the second material 3152 throughout theseal-forming structure 3100. For example, in an oral-nasal mask (i.e., apatient interface as illustrated in FIGS. 7-23 that seals around boththe nares and the mouth), the first material 3150 and the secondmaterial 3152 may be included on portions that seal around the patient'snose and on portions that seal around the patient's mouth. Although theymay be, both the first and second materials 3150, 3152 do not need to beused in equal amounts when forming the seal-forming structure 3100. Thefirst and second materials 3150, 3152 may be used at specific locationsin order to improve patient comfort and/or enhance sealing.

In some forms, the first material 3150 is silicone, or other similarlyflexible material. The silicone 3150 may be biocompatible so thatpatient does not experience discomfort while using the patient interface3000. Additionally, the silicone 3150 may be compliant and capable ofsealing with a variety of patients' facial structures.

In some forms, the second material 3152 is foam, although it may also bea textile or other similar material. Like the silicone of the firstmaterial 3150, the foam 3152 may be biocompatible, and not irritate thepatient when in contact with the patient's skin. The foam 3152 may besofter, lighter, and/or provide additional comfort as compared to thefirst material 3150.

In some forms, the foam 3152 may be constructed in portions of theseal-forming structure 3100 that contact regions of the patient's facewhere movement may occur. For example, these may include regions with avariety of contours, ridges, and/or creases (e.g., the nasal alarregion, the nasolabial sulcus, etc.), where the foam 3152 may berequired to deform in order to effectively seal against the patient'sface. The nasolabial sulcus, for example, is a region with skin may foldand/or crease as a result of the patient moving their mouth. The foam3152 may be effective at deforming with the patient's face in order tofill the creases (e.g., as the patient's mouth opens), and relax inorder to contact a flatter surface of the patient's skin (e.g., as thepatient's mouth closes and the creases flatten). This property allowsthe foam 3152 to dynamically adjust to changing facial contours, andmaintain an effective seal (e.g., by substantially eliminating leaks).

In some forms, the foam 3152 is permanently coupled to the silicone3150. In other words, the foam 3152 may not be removed without damagingthe patient interface 3000. The foam 3152 may be coupled to the silicone3150 using an adhesive and/or a mechanical fastener. Alternatively or inaddition, the silicone 3150 may be molded to the foam 3152.

In some forms, the foam 3152 is removably coupled to the silicone 3150,and may be removed by the patient. The patient may remove the foam 3152and replace with a separate piece of foam 3152 after a certain time(e.g., to provide a clean foam 3152). The patient may also interchangeone type of foam 3152 for another type of foam 3152 depending on patientpreference and/or comfort.

As shown in FIG. 29 , the patient interface 3000 includes a full facemask (e.g., an ultra-compact full face mask), that seals around thepatient's nares and around the patient's mouth (e.g., independently, orusing a single seal).

In some forms, the second seal forming structure 3102 may be constructedfrom silicone 3150. In other words, the portion of the seal-formingstructure 3100 that at least partially seals around the patient's naresis constructed from the first material 3150. The first material 3150 maycontact at least a portion of the patient's subnasale and/or thepatient's nasal ala. Additionally, the nasal apertures 3135 may beformed through the first material 3150.

In some forms, the first seal forming structure 3101 may be constructedfrom foam 3152. In other words, the portion of the seal-formingstructure 3100 that at least partially seals around the patient's mouthis constructed from the second material 3152. The second material 3152may contact the patient's lip inferior, and a lateral area outside ofthe patient's mouth width.

In certain forms, the foam of the second material 3152 may be structuredso that it is substantially impermeable in order to limit air leakingthrough the second material.

In certain forms, the foam of the second material 3152 may be permeablebut may be coated with an impermeable material (e.g., a silicone layer).The coating may be applied to an inner surface of the second material3152 (e.g., a surface within the cavity 3272) so that the patientcontacts the second material 3152 and not the coating. In other forms,the coating may be applied to the outer surface in addition or insteadof the inner surface.

In certain forms, a lip superior portion 3131 extends between lateralsides of the seal-forming structure 3100, and may separate the firstseal forming structure 3101 from the second seal forming structure 3102.The lip superior portion 3131 contacts the patient's lip superior inuse, and may be constructed from foam 3152.

In one form, the lip superior portion 3131 does not apply any sealingforce on the patient's lip superior while in use. Only the outerperimeter of the seal-forming structure 3100 forms a seal with thepatient's face. Thus, the first and second sealing structures 3101, 3102may cooperate to form the seal around the patient's nares and mouth.

In one form, the lip superior portion 3131 does apply a sealing force tothe patient's lip superior while in use. The position of the lipsuperior portion 3131 between the first and second sealing structures3101, 3102 may allow it to assist in forming a seal around both thenares and the mouth. Even when a seal is separately formed around eachorifice, both the patient's nares and the patient's mouth may be influid communication with the cavity 3272 of the plenum chamber 3200.

As shown in FIGS. 30 to 31A, the first and second seal formingstructures 3101, 3102 may be flush with one another. In other words,there may be a substantially smooth transition between the first sealforming structure 3101 and the second seal forming structure 3102. Thesmooth transition may be comfortable for the patient, and thereforeimprove patient compliance, because there is no substantially sharp, orotherwise uncomfortable, transition between the two materials.

As illustrated in FIG. 30A, the second material 3152 may be thicker thanthe first material 3150. This may be to improve impermeability of thesecond material 3152 and/or to improve patient comfort. Because thefirst material 3150 may be thinner than the second material 3152, thefirst material 3150 may not be flush with the second material 3152across the entire width of the second material 3152. Instead, the firstmaterial 3150 may be flush at the corner or ridge region 3120. Thisregion 3120 may be angled as described above in order to improve sealingwithout causing substantial discomfort. Alternatively, the ridge region3120 may be entirely smooth so that there is a constant radius ofcurvature on either side of the ridge region 3120. The first material3150 may only be flush with the second material 3152 at the patientcontacting side, and may not be flush with the second material 3152within the cavity 3272.

In some forms, the transition may be at the boundary 3103 between thesecond seal forming structure 3102 and the lip superior portion 3131.With specific reference to FIG. 31 , the lip superior portion 3131includes a curvature that substantially corresponds to the curvature ofthe second seal forming structure 3102, and to the remainder of thefirst seal forming structure 3101. A smooth, continuous surface mayextend between the first and second sealing structures 3101, 3102 (e.g.,there are no jagged and/or discontinuous portions).

As shown in FIG. 32 , the first seal forming structure 3101, includingthe lip superior portion 3131, may be constructed from a single piece offoam 3152. In other words, the entire first seal forming structure 3101is one piece, and may be moved together. This may assist in assemblingthe seal-forming structure 3100, because constructing the first sealforming structure 3101 as a single piece reduces the number ofcomponents limits the possibility that components are incorrectlypositioned relative to one another.

5.3.1.6.1 Shape of Foam

In some forms, the foam 3152 of the first seal forming structure 3101may include an annular shape, in order to provide an opening to receivethe patient's mouth. As described above, the foam 3152 contacts the areaaround the patient's mouth in order to seal around the orifice. Thepatient may desire a minimal width of the first seal forming structure3101 (e.g., the distance between an inner and outer diameter), becauseless material in contact with the patient's face may improve patientcomfort and compliance.

In some forms, the sealing perimeter of the first seal forming structure3101 is minimized in order to maximize patient comfort and compliance.Reducing the sealing perimeter (e.g., as close to the mouth width,and/or upper and/or lower vermillion as possible while still maintaininga seal around the patient's mouth) may reduce the feeling in the patientof wearing a medical device.

Reducing the sealing perimeter may also reduce the volume of the cavity3272. This may improve the efficiency of the system because less airflowis needed to reach the desired pressure in the cavity 3272.

Accordingly, if the outer diameter is already at its minimum (e.g., toestablish a minimum sealing perimeter), then the inner diameter may beadjusted to reduce the total contact area between the patient and thefirst seal forming structure 3101.

As shown in FIG. 32 , increasing the inner diameter (i.e., in order todecrease the width) of the foam 3152, the oral hole 3133 that receivesthe patient's mouth is larger (e.g., as compared to FIG. 29 ). A largeroral hole 3133 may improve patient comfort because they may have addedroom between their mouth and the foam 3152. This may provide the patientthe ability to move their lips without experiencing substantial contactwith the foam 3152.

The foam 3152 in the first seal forming structure 3101 may include anaverage width. The width may be substantially the same along the entireperimeter of the first seal forming structure 3101, so that the width ina given location is substantially the same as the average width. In someforms, the average width may be between approximately 1 mm andapproximately 20 mm. In some forms, the average width may be betweenapproximately 5 mm and approximately 15 mm. In some forms, the averagewith may be approximately 10 mm. This may be less than the average widthof the first seal forming structure 3101 in FIG. 29 , which may be atleast 15 mm.

In some forms, the width may very along the perimeter of the first sealforming structure 3101, although the average width may still be betweenapproximately 1 mm and approximately 20 mm. A variable width may allowthe first seal forming structure 3101 to be tailored to individualregions of a patient's face, and provide increased sealing and/orcushioning at some locations and less in others.

In some forms, the first seal forming structure 3101 may form asubstantially polygonal shape. In some examples, the first seal formingstructure 3101 may form a substantially trapezoidal shape. The lipsuperior portion 3131 may be the shorter substantially parallel side ofthe substantially trapezoidal shape.

In some forms, the first seal forming structure 3101 may include varyingthicknesses. For example, the foam 3152 at the lip superior portion 3131may be thinner than the adjacent foam 3152.

In certain forms, corners 3153 of the first seal forming structure 3101may be substantially squared. This may assist in reducing the feeling inthe patient that the foam 3152 is crowding their nose and/or mouth.

In certain forms, the lip superior portion 3131 may have a curvature.For example, the lip superior portion 3131 may have a positive curvaturerelative to the patient's subnasale. The minimum point of the lipsuperior portion 3131 may be proximate to the center of the lip superiorportion 3131. The curvature may also move the lip superior portion 3131away from the nostrils and reduce the likelihood of blocking orotherwise obstructing the nostrils.

In one form, only a portion of the lip superior portion 3131 may becurved. For example, a portion of the lip superior portion 3131 may bestraight, and a portion of the lip superior portion 3131 may be curved.In other words, only the central portion of the lip superior portion3131 may have the curvature.

In some forms, a transition 3154 between the straight section and thecurved section of the lip superior portion 3131 may be sharp. In otherwords, the transition 3154 may be substantially angled and not smooth.This may allow the foam 3152 of the lip superior portion 3131 to morereadily into small crevices of the patient's face (e.g., proximate tothe patient's nasal alas). This may improve sealing, since air may belimited from escaping through those regions. Since the foam 3152 iscompliant, the angled shape of the transition 3154 may not cause thepatient discomfort. The sharp edge of the foam 3152 may reduce thefeeling of occlusion, and therefore increase patient compliance.

However, as described above, this surface may alternatively be smooth,like the example illustrated in FIG. 31 .

As shown in FIG. 33 , the foam 3152 may have a substantially rectangularshape when viewed from a side (e.g., the left or right side) or incross-section. The rectangular profile may have sharp or angled edges,which may provide the benefit of allowing the foam 3152 to more readilyinto small crevices of the patient's face (e.g., between the patient'snasolabial sulcus and nasal ala). In other words, the edges of therectangular profile assists with the dynamic sealing, so that the foam3152 may more effectively deform into the creases on the patient's skinas they form, and return to the relaxed position as they flatten sominimal air leaks to the ambient from the plenum chamber 3200. The sharpedges may not cause the patient discomfort because of the compliantnature of the foam 3152.

In some forms, the rectangular profile may have rounded edges,specifically in regions of the foam 3152 configured to contact thepatient's face. The rounded edge may not extend entirely around theperimeter of the first seal forming structure 3101, and a portion of thefoam 3152 may have a space edge. The rounded portion may be proximateinferior portion of the first seal forming structure 3101, and may beconfigured to sit proximate to the patient's mouth. The sharp portionmay be proximate superior portion of the first seal forming structure3101, and may be configured to sit proximate to the patient's nose.

5.3.2 Plenum Chamber

In some forms, the plenum chamber 3200 (or at least a portion of theplenum chamber 3200) and the seal-forming structure 3100 are formed froma single homogeneous piece of material (e.g., molded silicone). Acombination of the seal-forming structure 3100 and the plenum chamber3200 may be considered a cushion.

5.3.2.1 Angle of Nasal Portion is Adjustable

With particular reference to FIGS. 9, 10 and 16 to 18-2 , in one form ofthe technology a first anterior wall portion 3240 of the nasal portion3202 of the plenum chamber 3200 is more flexible than an immediatelyadjacent region of the oral portion 3201. The first anterior wallportion 3240 may be provided adjacent a boundary 3241 of the nasal andoral portions of the plenum chamber 3200. In embodiments the firstanterior wall portion 3240 may be symmetrical about the mid-sagittalplane and may extend across at least 50% of the width of the nasalportion 3202 of the plenum chamber, for instance at least 80%. In someembodiments the first anterior wall portion 3240 may extend acrosssubstantially the entire width of the nasal portion 3202 of the plenumchamber.

In some forms of the technology a second anterior wall portion 3242 isless flexible than the immediately adjacent portions of the anteriorwall. In some embodiments the second anterior wall portion 3242 isimmediately adjacent the first anterior wall portion 3240 on an oppositeside to the boundary 3241 of the nasal and oral portions of the plenumchamber. In embodiments the second anterior wall portion 3242 may besymmetrical about the mid-sagittal plane and may extend across at least50% of the width of the nasal portion 3202 of the plenum chamber, forinstance at least 80%. In some embodiments the second anterior wallportion 3242 may extend across substantially the entire width of thenasal portion 3202 of the plenum chamber.

The flexible first anterior wall portion 3240 may allow the patientcontacting portions 3110 of the second seal forming structure 3102 topivot or hinge about a region on the posterior side of the interface3000. This may assist in allowing the interface to accommodate patientswith a variety of angles between the bottom of the nose and the top lip(i.e. nasolabial angles).

In embodiments featuring a corner or ridge 3120 between the first andsecond seal forming structures 3101, 3102, such as have been describedabove, the patient contacting portions 3110 may pivot or hinge about anarea at or adjacent the corner or ridge 3120. In embodiments providedwith one or more support portions 3260 (described further below), thehinging or pivoting region may be immediately superior to the supportportions 3260.

As shown in FIG. 9 , the first anterior wall portion 3240 may have asuperior boundary 3243 and an inferior boundary 3244. One or both of thesuperior and inferior boundaries 3243, 3244 may be curved, for examplesuch that a central portion of the boundary is inferior to the lateralportions, as shown. The first anterior wall portion 3240 may besubstantially the same height across its width (i.e., the superior andinferior boundaries may be substantially parallel) or the height mayvary across the width, for example such that the height of a centralportion of the first anterior wall portion 3240 is greater than theheight of the lateral portions, as shown in the embodiment in FIG. 9 .Varying the curvature of one or both of the boundaries 3243, 3244 and/orthe height of the first anterior wall portion 3240 may change thestiffness of the first anterior wall portion 3240, that is, itsresistance to collapsing or folding in response to forces on thepatient-contacting portions 3110 of the second seal forming structure3102.

Similarly, the second anterior wall portion 3242 may have a superiorboundary 3247 and an inferior boundary 3248. In some forms of thetechnology the inferior boundary 3248 of the second anterior wallportion 3242 is the same as the superior boundary 3243 of the firstanterior wall portion 3240. Both the superior and inferior boundaries3247, 3248 of the second anterior wall portion 3242 may be curved, forexample such that a central portion of the boundary is inferior to thelateral portions. The second anterior wall portion 3242 may besubstantially the same height across its width (i.e., the superior andinferior boundaries may be substantially parallel) or the height mayvary across the width, for example such that the height of a centralportion of the second anterior wall portion 3242 is less than the heightof the lateral portions.

In some forms of the technology other ways of configuring the firstanterior wall portion 3240 to have a required stiffness may be used, inaddition to or alternatively to curved boundaries. For example, thethickness of the first anterior wall portion 3240 may be selected toprovide a required stiffness. In examples the first anterior wallportion 3240 may be thinner than the immediately adjacent portions ofthe plenum chamber wall. Additionally and/or alternatively, the firstanterior wall portion 3240 may extend in a superior direction around alateral edge of the second anterior wall portion 3242, as shown in FIG.21 , thereby providing a reduced stiffness/resistance to compression orcollapse compared to embodiments in which the first anterior wallportion 3240 is not shaped this way.

The second anterior wall portion 3242 (e.g., the band 3270) may assistin preventing collapse of the nasal portion 3202, and may providesupport for the patient-contacting portions 3110 of the second sealforming structure 3102, which are typically relatively thin.Insufficiently supported patient contacting portions may suffer fromblowout of the sealing engagement with the patient's face. In one formthe second anterior wall portion 3242 is thicker than the immediatelyadjacent portions of the plenum chamber wall. In certain forms thesecond anterior wall portion 3242 is provided as a thickened band ofmaterial 3270, as shown in FIGS. 16-19 . The first and second anteriorwall portions 3240, 3242 may be made from the same material, for exampleas part of an integrally moulded shell 3250.

In some forms, the first and second anterior wall portions 3240, 3242may include different thicknesses. For example, the thickness of thesecond anterior wall portion 3242 may be greater than the thickness ofthe first anterior wall portion 3240, which may provide the increasedstiffness in the second anterior wall portion 3242 (e.g., as compared tothe first anterior wall portion 3240). Specifically, the second anteriorwall portion 3242 may be a band 3270 that may extend into the cavity3272 of the plenum chamber 3200. For example, the band 3270 may extendpast the first anterior wall portion 3240, and extend toward a patientwearing the patient interface 3000. An exterior surface of the nasalportion 3202 may be substantially smooth, while an interior surface ofthe nasal portion (e.g., within the cavity 3272) may be stepped (orotherwise include a discontinuity).

As shown in FIGS. 16-1 and 16-2 , the first anterior wall portion 3240may act as a hinge and allow the nasal portion 3202 to bend. The firstanterior wall portion 3240 may be the thinnest region of the nasalportion 3202, and therefore may be the most susceptible to a bendingmoment. The increased thickness of the band 3270 directs the bendingmoment away from the second anterior wall portion 3242, and toward thethinner first anterior wall portion 3240. A larger height of the band3270 (i.e., a larger distance between the superior and inferiorboundaries 3247, 3248) may also make the nasal portion 3202 stiffer andless capable of bending about the first anterior wall portion 3240. Thefirst and second anterior wall portions 3240, 3242 may move in theanterior direction (e.g., away from the patient) as bending occurs.

As shown in FIGS. 18-1 and 18-2 , the superior boundary 3243 of thefirst anterior wall portion 3240 is not the same as the inferiorboundary 3248 of the second anterior wall portion 3242. Instead, thesuperior boundary 3243 is a least partially more superior than theinferior boundary 3248, and may be at least partially aligned with thesuperior boundary 3247 of the second anterior wall portion 3242. Thisallows the first anterior wall portion 3240 to be disposed at leastpartially alongside of the band 3270 (e.g., and surround the band 3270on two or more sides). In other words, the first anterior wall portion3240 may be disposed on at least one of the ends of the band 3270. Thismay provide the first anterior wall portion 3240 with greaterflexibility so that the nasal portion 3202 is able to bend further(e.g., in the anterior direction).

As shown in FIG. 21-1 , the nasal portion 3202 may also be formedwithout a hinge. In other words, a band may not be formed on the secondanterior wall portion 3242, so that the first and second anterior wallportions 3240, 3242 have substantially uniform thicknesses. The nasalportion 3202 may still be able to bend even without band because it maybe constructed from silicone, which permits some compliance in the nasalportion 3202 to accommodate different nasolabial angles.

5.3.2.2 Flexible Shell

In some forms of the technology the shell 3250 may be made from a rigidmaterial such as polycarbonate. However, in other forms of thetechnology the shell 3250, or portions of the shell 3250, may besomewhat flexible. For example, in examples the shell 3250 may be formedfrom a material which has a Young's modulus of 0.4 GPa or lower, forexample foam. In some forms of the technology the shell 3250 may be madefrom a material having Young's modulus of 0.1 GPa or lower, for examplerubber. In other forms of the technology the shell 3250 may be made froma material having a Young's modulus of 0.7 MPa or less, for examplebetween 0.7 MPa and 0.3 MPa. An example of such a material is silicone.

In examples, the shell 3250 and one or both of the first and second sealforming structures 3101, 3102 may be formed from the same material(e.g., silicone, textile, etc.).

In some forms of the technology (see e.g., FIGS. 23 to 28 ), the shell3250 may be constructed substantially entirely from a flexible material,which may provide the shell 3250 with the greatest freedom of movement(i.e., substantially no rigid and/or thickened portions that limitbending). The shell 3250 may be sufficiently flexible that one or morecomponents are added to provide a required stiffness in one or moreareas or regions of the shell 3250 (e.g., a region that contacts thearea 1010). For example, one or more of a vent module; a connectionport; a headgear connector; a headgear connector connected to arigidising arm and a rigidising member may be connected to the shell3250 in such a way as to increase the stiffness of the plenum chamber3200 in the area adjacent the component, for example as describedfurther below. In some forms of the technology such components may bereleasably connectable to the flexible shell 3250. Additionally oralternatively one more components may be permanently connected to theshell 3250, for example by bonding and/or overmoulding. The rigidisingmember may also serve to increase the stiffness and/or support the shapeof the seal forming structure 3100.

In some forms of the technology the shell 3250 may be generally flexiblebut may comprise stiffening portions having greater thickness thanimmediately adjacent portions of the shell 3250. Such stiffeningportions may be configured as ribs or bands, for example extendinglaterally across the shell and/or extending in a superior-inferiordirection, although many other configurations are possible. In someforms the shell may comprise a substantially rigid portion, for examplemanufactured from polycarbonate, as well as a somewhat flexible portion.

In some forms of the technology it may be preferable for a centralportion 3251 of the anterior side of the oral portion 3201 of the plenumchamber to have a greater stiffness than the remainder of the plenumchamber 3200. In some forms of the technology the area of increasedstiffness may be immediately inferior to the nasal portion 3202, asshown in FIG. 21 and described further below, and/or immediatelysuperior to the oral portion 3201. In one form of the technology, aportion of, or the entirety of, the first anterior wall portion 3240 maybe an area of increased stiffness, rather than an area of increasedflexibility. Providing increased stiffness in one or more of these areasmay provide shape stability and may limit the extent to which the shell3250 deforms as a result of headgear forces. Excessive deformation mayresult in the second seal forming structure 3102 occluding the nares.Avoiding such deformation may be particularly advantageous to patientswith relatively wide noses, and may be less important, or in some casesundesirable, for patients with narrow noses. In addition, the areas ofincreased stiffness described may assist in reducing torsionaldeformation of the interface which may otherwise result in one side ofthe second seal forming structure 3102 losing contact with the patient'snose, thereby creating a leak path.

As shown in FIGS. 21 and 21-1 , in one form of the technology the shell3250 may be provided with a rigid portion 3263, or at least a portionwhich is more rigid than the remainder of the shell, to which one ormore connection ports 3600 are provided, e.g. moulded. In one form ofthe technology a rigid portion 3263 may be made from polycarbonate. Thismay provide more rigidity than a shell made exclusively of silicone. Inone form the technology holes forming a vent 3400 are moulded into therigid portion 3263. In some forms of the technology connectors 3310 fora positioning and stabilising structure are mounted on arms 3320 whichprovide some rigidity to the shell.

In one form of the technology the rigid portion 3263 extends laterallyacross the anterior of the plenum chamber near a superior boundary ofthe first anterior wall portion 3240, for example immediately below thesecond anterior wall portion 3242. The rigid portion 3263 may extendcontinuously between the connection ports 3600, and may provide anairflow path for the flow of pressurized air entering the plenum chamber3200 through the connection ports 3600.

In some forms of the technology the connection ports 3600 may have asubstantially elliptical shape in cross-section. The connection ports3600 may be orientated such that a centreline of each port issubstantially parallel to an exterior surface of the plenum chamberadjacent the port.

In some forms of the technology the rigid portion 3263 may protrude inan anterior direction relative to an adjacent face of the first anteriorwall portion 3240, and may be shaped to increase resistance to bending.

In some forms of the technology (see e.g., FIG. 21 ), the connectors3310 and arms 3320 are provided inferior of the connection ports 3600,toward the lateral edges of the plenum chamber 3200. The connectors 3310may be provided at lateral ends of the arms 3320. The connectors 3310may provide additional rigidity to the plenum chamber 3200 and/or theseal forming structure 3100.

In some forms of the technology (see e.g., FIG. 21-1 ), the connectors3310 do not include arms 3320, and are instead connected directly to theplenum chamber 3200. This may make the plenum chamber 3200 more flexiblethan the plenum chamber 3200 of FIG. 21 .

FIG. 22 shows a plenum chamber 3200 with a vent mounting aperture 3410into which a suitable vent portion or module may be inserted. The ventportion may be made from a relatively stiff material to increase thestiffness of the plenum chamber. In some forms of the technology thevent mounting aperture 3410 may be substantially elliptical in shape,with the minor axis of the ellipse being substantially parallel to asagittal plane.

In the embodiment shown in FIG. 22 the vent mounting aperture isprovided toward a superior border of the oral portion 3201 of the plenumchamber 3200.

The embodiment shown in FIG. 22 is provided with connectors 3310 for apositioning and stabilising structure. The connectors 3310 may bemounted in relatively thicker regions of the shell 3250. In theembodiment shown the connectors 3310 are inferior of the vent mountingaperture 3410 and toward the lateral sides of the plenum chamber 3200.In some forms of the technology the connectors 3310 are substantiallycircular magnetic headgear connectors.

While inlet or connections ports are not shown in the drawings of theplenum chamber shown in FIGS. 7-19 , those skilled in the art willappreciate that in practice one or more inlet ports will be provided,for example inlet ports 3600 as shown in FIGS. 21-22 . The inlet ports3600 allow connection of the interface to an air circuit 4170, asdescribed further herein. In some forms of the technology one or morecomponents of the air circuit 4170 may also act as components of apositioning and stabilising structure.

In certain forms of the present technology, the plenum chamber 3200 isconstructed from a transparent material, e.g. a transparentpolycarbonate. The use of a transparent material can reduce theobtrusiveness of the patient interface, and help improve compliance withtherapy. The use of a transparent material can aid a clinician toobserve how the patient interface is located and functioning.

In certain forms of the present technology, the plenum chamber 3200 isconstructed from a translucent material, e.g. translucent silicone. Theuse of a translucent material can reduce the obtrusiveness of thepatient interface, and help improve compliance with therapy.

In certain forms of the present technology, dedicated stiffening membersor rigidising members (e.g., with no other function) may be included onthe plenum chamber 3200. These members may be formed from a materialmore rigid than the plenum chamber 3200 (e.g., than the silicone). Thededicated stiffening members may be overmolded to the plenum chamber3200 to provide more stiffness than the rigid portion 3263 of the shell3250 or the arms 3320.

5.3.2.3 Mounting Flange

As shown in FIGS. 34 and 35 , some forms of the plenum chamber 3200include a mounting flange or support surface 3290. The mounting flange3290 may be a substantially flat surface. The mounting flange 3290 maybe perpendicular to the anterior-posterior direction (e.g., a directionparallel to the patient's sagittal plane) when worn by the patient.

In some forms, the mounting flange 3290 includes a first free end 3291and a second free end 3292 spaced apart from the first free end 3291.Thus, the mounting flange 3290 may not form a continuous annular shape.A space or gap 3293 between the first and second free ends 3291, 3292may be proximate the patient's lip superior when the plenum chamber 3200is in use.

In certain forms, the mounting flange 3290 may have a substantiallyC-shape, where a portion of the mounting flange 3290 extends toward thepatient's philtrum in use.

In certain forms, the mounting flange 3290 may have a substantiallyU-shape, where the mounting flange 3290 does not extend toward thepatient's philtrum in use.

In some forms, the plenum chamber 3200, with the mounting flange 3290,is constructed together with the second seal forming structure 3102. Forexample, the plenum chamber 3200 and the second seal forming structure3102 may be constructed from the same material (e.g., silicone), and maybe molded together. Although in other forms, the plenum chamber 3200 maybe constructed at least partially from a different material (e.g., hardplastic) than the second seal forming structure 3102. In still otherforms, the mounting flange 3290 and the second seal forming structuremay be constructed from the same material, but the mounting flange 3290may be thicker or otherwise stiffer.

In some forms, the second seal forming structure 3102 may extend beyondthe mounting flange 3290 in the posterior direction. In other words, thesecond seal forming structure may form an overhang 3294 with respect tothe mounting flange 3290.

In some forms, the second seal forming structure 3102 includes twooverhangs 3294, which may be positioned on either lateral side of thepatient's nose, when the patient interface 3000 is worn by the patient.The overhangs 3294 of the second seal forming structure 3102 may notextend across the gap 3293. Rather, the overhangs 3294 may extend up tothe respective first and second free ends 3291, 3292, so that a width ofthe gap 3293 may not be obstructed by the overhangs 3294.

In certain forms, the width of the gap 3293 is substantially the widthof a patient's nose. In use, the patient's nose may fit into the gap3293 so that the overhangs 3294 may be disposed on either side of thepatient's nose. An inner surface of each overhang 3294 may contact thepatient proximate their respective nasal ala.

As shown in FIG. 35 , a lower surface 3295 of each overhang 3294 may besubstantially flat, and may be formed perpendicularly with the supportflange 3290. An upper surface 3296 of each overhang 3294 may be inclinedand/or curved so that the thickness of each overhang 3294 may decreasein the posterior direction. Thus, the thickness of each overhang 3294may be greater proximate to the mounting flange 3290, and less distal tothe mounting flange 3290.

In some forms, connection ports 3600 (described below) may be moldedwith the plenum chamber 3200 and the second seal forming structure 3102.In other words, the connection ports 3600 may be formed as one piecewith the plenum chamber 3200, and may not be removable from the plenumchamber 3200.

As shown in FIG. 31 , some forms of the patient interface 3000 includeconnection ports 3600 that are spaced apart from the support flange3290. For example, the connection ports 3600 may be more anterior thanthe support flange 3290 while the patient interface 3000 is in use. Inthis way, the support flange 3290 may be unobstructed by the connectionports 3600 or the air circuit 4170 (described below).

As shown in FIG. 33 , certain forms of the patient interface 3000 mayinclude connection ports 3600 that are oriented offset from thesuperior-inferior direction (e.g., as opposed to being positionedgenerally along the superior-inferior direction of FIG. 31 ). Duringassembly for example, a superior end of the connection port 3600 may berotated toward the patient and an inferior end of the connection port3600 may be rotated away from the patient (i.e., in a clockwisedirection as shown in FIG. 33 ).

In some forms, the connection ports may have a substantially straightsurface 3604 that may be inclined relative to the mounting flange 3290.

In certain forms, the connection ports 3600 may be substantiallyD-shaped, and the straight surface 3604 may be proximate to the mountingflange 3290.

Rotating the connector ports 3600 may cause the patient interface 3000to be worn in a rotated position. For example, when in use, theconnector ports 3600 may be aligned with the superior-inferiordirection. Since the connector ports 3600 were rotated (e.g., duringassembly), the plenum chamber 3200 must be rotated (e.g., when donning)in the opposite direction (e.g., counter clockwise as viewed in FIG. 33) in order to orient the connector ports 3600 as described above. Thiscauses the plenum chamber 3200 to be rotated in a direction away fromthe patient's nose and toward the patient's mouth. Rotating away fromthe patient's nose may reduce the load experienced by a patientproximate their pronasale (e.g., around an alar perimeter), or insimilar areas where excessive loading may be uncomfortable for apatient. It may also give the patient's nose more room within the cavity3272 so that the patient's nose does not contact or “bottom out” againsta surface of the plenum chamber before a seal has been sufficientlyestablished.

For example, as illustrated in FIG. 33 , the mounting flange 3290 isoriented generally along the superior-inferior axis of the page. Thestraight surface 3604 is inclined relative to the superior-inferiordirection. In use, the patient interface 3000 may rotate (e.g., in thecounter clockwise direction of FIG. 33 ) from the position illustratedin FIG. 33 toward the position illustrated in FIG. 19 so that thestraight surface of FIG. 3604 is more closely aligned with thesuperior-inferior direction of the page (and may also be substantiallyparallel to the patient's sagittal plane).

In this position, the tensile force provided by the conduits connectedto the connection port 3600 (or from straps of the positioning andstabilizing structure 3000) may pull the first seal forming structure3101 into the patient's face with more force than the second sealforming structure 3102, which may be more comfortable for the patient.

5.3.2.3.1 Connection with the First Seal Forming Structure

In some forms, the first seal forming structure 3101 may be coupled tothe plenum chamber 3200, after the plenum chamber 3200 has beenconstructed (e.g., after the plenum chamber 320 and the second sealforming structure 3102 are molded together).

In some forms, the mounting flange 3290 provides a mounting surface forthe first seal forming structure 3101. The first seal forming structure3101 may be coupled to the mounting flange 3290 so that it is positionedto contact the patient's face in use. The first seal forming structure3101 may be coupled to the mounting flange 3290 using adhesives (e.g.,glue), mechanical fasteners (e.g., snaps, clasps, etc.), magnets, hookand loop material, or any other similar connection means. Additionally,a combination of two or more connection means may be used.

As shown in FIGS. 32 and 33 , the foam 3152 that forms the first sealforming structure 3101 may be constructed from a single piece ofmaterial. When coupled to the mounting flange 3290, a portion of thefoam 3152 extends across the gap 3293 between the first and second freeends 3291, 3292, so that unlike the mounting flange 3290, the foam mayextend around an entire perimeter of the patient's mouth.

In certain forms, the foam 3152 spanning the gap 3293 is unbacked. Inother words, the foam 3152 spanning the gap 3293 is unsupported, and maymove into and/or out of the cavity 3272 of the plenum chamber 3200. Theremainder of the foam 3152 is supported by the mounting flange 3290 andis not free to move, although it may compress as a result of contactwith a patient's face. For example, as illustrated in FIG. 31A, the foam3152 configured to contact the patient's lip superior is unbacked, andmay therefore be movable relative to the remainder of the foam 3152(e.g., which contacts the mounting flange 3290).

In use, at least part of the lip superior portion 3131 of the first sealforming structure 3101 spans the gap 3293 and is unsupported by themounting flange 3290. Thus, the patient's lip superior (e.g., thepatient's philtrum) may contact the unsupported section of the foam3152. As the patient dons the patient interface 3000, the lip superiorportion 3131 may move at least partially into the cavity 3272 (e.g., asa result of a force applied by the patient's lip superior). When thepatient doffs the patient interface, the lip superior portion 3131 maymove in the opposite direction to return to its substantially initialposition.

In certain forms, the movement of the lip superior portion 3131 mayprovide additional comfort for the patient wearing the patientinterface. For example, the lip superior portion 3131 may be under sometension prior to contact with the patient's lip superior. As the patientcontacts the lip superior portion 3131, the tension increases andprovides a support surface for the patient's lip superior. Patients witha variety of sized lip superiors may experience substantially similarsupport (i.e., via the tension in the lip superior portion 3131).

With continued reference to FIG. 33 , the foam 3152 of the first sealforming structure 3101 may be substantially flush with the second sealforming structure 3102. This may form a substantially continuous surfacewithout discontinuities in order to limit discomfort for a patientdonning the patient interface 3000.

In some forms, the foam 3152 may contact the lower surface 3295 afterbeing coupled to the support flange 3290. The foam 3152 may be pressedagainst the lower surface 3295 so that there is no gap between the firstseal forming structure 3101 and the second seal forming structure 3102along either overhang 3294.

In some forms, the foam 3152 and the overhangs 3294 may extend to thesame position in the posterior direction. In other words, the overhangs3294 and the foam 3152 may extend up to a common plane (e.g., a planesubstantially parallel to the coronal plane of the patient). This maylimit the patient from unevenly contacting the seal-forming structure3100, which may reduce patient comfort (e.g., because the seal formingstructure 3101, 3102 that extends further in the posterior direction maydig into the patient and cause irritation as the patient continues topush the seal-forming structure 3100 against their face in order toproperly orient the seal-forming structure 3100). The compliant natureof the materials (e.g., foam and silicone) that comprise the first andsecond seal forming structures 3101, 3102 allow both to compress so thatthey maintain a substantially constant surface while the patientinterface 3000 is worn. Additionally, since the first and second sealforming structures 3101, 3102 are coupled together (e.g., via anadhesive), they generally move together when compressed, although onematerial (e.g., the foam 3152) may be more compliant than the othermaterial (e.g., so the compressed surface may be slanted and/or curved).

In use, the foam 3152 of the first seal forming structure 3101 mayprovide the patient with comfort from using a soft, compliant material.The low density and weight of foam (e.g., as compared to silicone,plastic, etc.) may provide additional comfort for the patient (e.g.,because the patient interface 3000 is lighter and more comfortable incontact with the patient's skin). Additionally, the foam 3152 may beeffective at sealing against the patient's face proximate to thecommissure (i.e., the corner of the mouth) and/or the nasal alar region(i.e., corner of nose), where there are numerous crevices that maydisrupt sealing. The foam 3152 may deform into these crevices as aresult of contact with the patient's face, in order to limit air fromescaping from the plenum chamber 3200.

When worn by the patient, the silicone 3150 contacts, and at leastpartially seals around, the patient's nares, and the foam 3152 contacts,and at least partially seals around, the patient's mouth. As describedabove, the foam 3152 is positioned around the mouth in order to sealwith the complex facial topography that exists around the mouth.However, sealing with foam 3152 may require a greater force than withanother material, like silicone 3150. Thus, the patient may experience agreater force around their mouth in order to create the therapeuticallyeffective seal. The area around the patient's mouth may be adapted tohandle greater forces, and thus the forces necessary to seal using foam3152 may not cause the patient discomfort.

However, the patient's nose and nasal region may be more sensitive, andthe forces used to seal the foam 3152 against the patient's face may becomfortable if experienced around the patient's nose. Thus, silicone3150 is used to seal around the patient's nares, because a lower sealingforce is required in order to achieve a therapeutically effective seal.Therefore, patient comfort around the nose may be balanced with sealeffectiveness around the mouth, so that a material is selected that mayoptimize sealing based on facial topography and/or sensitivity.Different forces may be achieved by separately adjusting upper and lowerstraps of the positioning and stabilizing structure 3300, so thatdifferent components of the overall force provided by the positioningand stabilizing structure 3300 are provided to each material 3150, 3152.

In some forms, the foam 3152 may not be air impermeable, but is capableof maintaining therapeutic pressure within the plenum chamber 3200because of the mounting flange 3290. In other words, since the mountingflange 3290 may be formed from an air impermeable material (e.g.,silicone), air may be unable to reach the foam 3152 and pass through.The deformation of the foam 3152 simply allows for a tighter (and moreindividualized) fit, so that the mounting flange 3290 or the second sealforming structure 3102 are tight against the patient's face.

In some forms, since the lip superior portion 3131 is not backed by themounting flange 3290 (or an air impermeable material like a siliconemembrane), air is able to pass through the lip superior portion 3131. Inother words, the seal-forming structure 3100 may not seal against theentire lip superior of the patient. Specifically, the lip superiorportion 3131 may not seal against the patient's philtrum. This mayprovide additional comfort to a patient, since less surface area oftheir face is subject to a seal. Since the lip superior portion 3131(and specifically the portion which contacts the patient's philtrum) iswithin the outermost perimeter of the seal-forming structure 3100,pressurized air may not leak from the plenum chamber 3200 through thelip superior portion 3131.

In certain forms, the unbacked lip superior portion 3131 may be thinnerthan the adjacent foam 3152 that contacts the mounting flange 3290. Thethinner lip superior portion 3131 may allow for easier movement into theplenum chamber 3200.

In some forms, the foam 3152 is air impermeable or is backed with an airimpermeable membrane. The impermeability of the foam 3152 may work inconjunction with the mounting flange 3290 in order to seal at leastpartially around the patient's mouth.

For example, inner sides of the foam 3152 may be backed with animpermeable material as described above. These sides of the foam 3152form the opening to the oral hole 3133 and are within the pressurizedvolume when the patient interface is in use, but are not in contact withthe mounting flange 3290. The impermeable membrane may be applied inorder to limit pressurized air from escaping the cavity. However, thesesurfaces are not in contact with the patient's skin, and so thepatient's skin may still contact the foam 3152 and not the membrane.

In other forms, at least a portion of the foam 3152 may not be backedwith an impermeable membrane. For example, the lip superior portion 3131that is unsupported by the mounting flange 3290 may be unbacked. Whenthe seal-forming structure 3100 is in contact with the patient's face,the unsupported section of the lip superior portion 3131 is within thesealing perimeter, and sealing is not necessary (e.g., airflow leakingthrough the unsupported section of the lip superior portion 3131 remainswithin the sealing perimeter). Additionally, as described previously,sealing against the patient's lip superior may be uncomfortable. Notincluding a backing membrane on the unsupported section of the lipsuperior portion 3131 may allow airflow to leak through the foam 3152and contact the patient's lip. This flow of air may assist in coolingthe patient's skin so that the patient interface 3000 may be morecomfortable.

As shown in FIGS. 36-38 , the foam 3152 may also comprise theseal-forming structure 3100 of a nasal only mask. The foam 3152 may besimilarly assembly to the plenum chamber 3200 (e.g., by using anadhesive on a mounting flange 3290) as in the full face mask describedabove. Additionally, many of the benefits of including a foam surfacemay also apply to the patient interface 3000 of FIGS. 36-38 . At leastsome of the similarities and differences are described below.

Since a nasal only mask does not seal around the patient's mouth (i.e.,the patient's upper and lower vermillion are not positioned within theplenum chamber 3200), the first material and the second material (e.g.,foam and silicone) make up the first seal-forming structure 3101.

In some forms, the foam 3152 is inferior to the silicone of theseal-forming structure 3100. The foam 3152 may contact the patient's lipsuperior. The foam 3152 may seal against the patient's philtrum sincethe outer perimeter of the seal-forming structure 3100 contacts thepatient's lip superior.

In the illustrated example, the foam 3152 may not be positioned aroundthe nasal apertures 3135. In other forms, the foam 3152 may not form aperimeter of the nasal apertures 3135. As shown in FIG. 37 , the firstmaterial 3150 may form the perimeter of the nasal apertures 3135, andthere may be a length of the first material 3150 between the edge of anasal aperture 3135 and the foam 3152. Additionally, the foam 3152 maycontact the mounting flange 3290 and the overhang 3294 so that the foam3152 does not form a surface of the cavity of the plenum chamber 3200.The foam 3152 may not need to be backed with an impermeable membrane asa result.

5.3.3 Support Portions

As best seen in FIGS. 12 and 14-18 , in one form of the technologysupport portions 3260 are provided on opposite sides of the interface3000 between the second seal forming structure 3102 and an anterior wallof the plenum chamber 3200. As shown in FIG. 12 , in an example eachsupport portion 3260 extends to a lateral edge of the interface.

The support portions 3260 do not act as undercushions and are insteadconfigured to resist or hinder compression in the anterior-posteriordirection. The support portions 3260 thereby support and/or stiffenportions of the second seal forming structure 3102 which engages thepatient's lip superior. In particular, the support portions 3260 maysupport and/or stiffen regions of the second seal forming structure 3102that may contact an area 1010 of the patient's face proximate theentrances to the nares where the ala meets the area above the lipsuperior, as shown in FIG. 20 . In other words, the area 1010 may bedirectly inferior to each of the lower corners of the patient's nose.

The support portions 3260 assist in ensuring that creases do not form inthe seal forming structure 3100. Creases in a seal forming structure mayform as a result of a very flexible seal forming structure, with a largeradius of curvature, conforming to a patient's face. The seal formingstructure may fold over itself, or crease, as a result of being tooflexible, and lead to leaks in the seal forming structure. Creasing maybe particularly of concern where the seal forming structure sealsagainst the area 1010 of the patient's face. The support portions 3260may be particularly advantageous when the seal forming structure isconfigured to create a corner and/or ridge 3120 as described herein. Thecorner and/or ridge 3120 may be a sharper curve (e.g., a curve with alower radius of curvature) as compared to seal forming structureswithout the support portions 3260. The support and/or stiffness added bythe support portions 3260 decreases the ability of the second sealforming structure 3102 from conforming to the patient's face. In orderto retain comfort for the patient, the corner and/or ridge 3120 isselected and/or sized to substantially match the geometry (e.g.,contours) of the patient's face. For example, the seal forming structure3100 for a particular patient may be selected from a variety of sizes inorder to substantially conform to the nasal alar region (i.e., proximateto the area 1010). The sharper curvature permits the second seal formingstructure 3102 to seal against the various crevices around the patient'snose with reduced likelihood that creases will form.

As seen in FIGS. 14-16 in particular, in one form of the technology thesupport portions 3260 are connected to the anterior side of the oralportion 3201 of the plenum chamber adjacent the boundary 3241 of theoral portion 3201 and the nasal portion 3202. In some embodiments thesupport portion 3260 may be curved when viewed in cross-section parallelto a sagittal plane (as shown in FIGS. 16-18 ) and/or when viewed incross-section parallel to a frontal plane (as shown in FIGS. 14 and 15). The curvature may be positive or negative. In the illustratedexample, the curvature may be negative (e.g., with respect to thepatient's nose). In some examples, a lateral side wall portion 3245 ofthe plenum chamber 3200 may curve inwardly adjacent the boundary 3241with the nasal portion 3202, and the support portion 3260 may besubstantially contiguous with an adjacent lateral side wall portion3245. As shown in FIG. 18 , when viewed in cross-section parallel to asagittal plane, at least a portion of the support portion 3260 mayreduce in thickness between a first end 3261 adjacent the anterior wallof the plenum chamber 3200 and a second end 3262 adjacent the sealforming structure 3100. For example, the support portion 3260 may bethicker proximate to the first end 3261, which may assist in providingincreased support and/or stiffness to the second seal forming structure3102. In some examples, the support portion 3260 may vary between athickness of 0.1 mm (e.g., proximate to the second end 3262), and athickness of 3.5 mm (e.g., proximate to the first end 3261). In someexamples, the support portion 3260 may vary between a thickness of 0.3mm (e.g., proximate to the second end 3262), and a thickness of 3 mm(e.g., proximate to the first end 3261). In some examples, the supportportion 3260 may vary between a thickness of 1.3 mm (e.g., proximate tothe second end 3262), and a thickness of 2.5 mm (e.g., proximate to thefirst end 3261).

Support portions 3260 with different geometries may be used fordifferent patients. For example, patient's that require more supportand/or stiffness in the second seal forming structure 3102 may use aseal forming structure 3100 with a thicker (e.g., proximate to the firstend 3261 and/or at any location along the length) and/or more curved(e.g., lower radius of curvature) support portion 3260. For example,patients that want a more flexible second seal forming structure 3102may use a seal forming structure 3100 with a thinner (e.g., proximate tothe first end 3261 and/or at any location along the length) and/or lesscurved (e.g., greater radius of curvature) support portion 3260.

As seen in particular in FIGS. 14 and 15 , in one form of the technologythe support portion 3260 is connected to the oral portion 3201 of theplenum chamber adjacent a boundary of a lateral side wall portion 3245of the oral portion 3201 and a lateral side wall portion 3246 of thenasal portion 3202.

In some forms of the technology, the support portions 3260 are shaped toprovide a substantially clear flow path from the oral portion 3201 ofthe plenum chamber to the nasal aperture(s) 3135 during inspiration. Insome forms of the technology no part of either support portion 3260 isdirectly inferior to the nasal aperture(s) 3135.

5.3.4 Positioning and Stabilising Structure

The seal-forming structure 3100 of the patient interface 3000 of thepresent technology may be held in sealing position in use by thepositioning and stabilising structure 3300.

In one form the positioning and stabilising structure 3300 provides aretention force at least sufficient to overcome the effect of thepositive pressure in the plenum chamber 3200 to lift off the face.

In one form the positioning and stabilising structure 3300 provides aretention force to overcome the effect of the gravitational force on thepatient interface 3000.

In one form the positioning and stabilising structure 3300 provides aretention force as a safety margin to overcome the potential effect ofdisrupting forces on the patient interface 3000, such as from tube drag,or accidental interference with the patient interface.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured in a manner consistentwith being worn by a patient while sleeping. In one example thepositioning and stabilising structure 3300 has a low profile, orcross-sectional thickness, to reduce the perceived or actual bulk of theapparatus. In one example, the positioning and stabilising structure3300 comprises at least one strap having a rectangular cross-section. Inone example the positioning and stabilising structure 3300 comprises atleast one flat strap.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured so as not to be too largeand bulky to prevent the patient from lying in a supine sleepingposition with a back region of the patient's head on a pillow.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided that is configured so as not to be too largeand bulky to prevent the patient from lying in a side sleeping positionwith a side region of the patient's head on a pillow.

In one form of the present technology, a positioning and stabilisingstructure 3300 is provided with a decoupling portion located between ananterior portion of the positioning and stabilising structure 3300, anda posterior portion of the positioning and stabilising structure 3300.The decoupling portion does not resist compression and may be, e.g. aflexible or floppy strap. The decoupling portion is constructed andarranged so that when the patient lies with their head on a pillow, thepresence of the decoupling portion prevents a force on the posteriorportion from being transmitted along the positioning and stabilisingstructure 3300 and disrupting the seal.

In one form of the present technology, a positioning and stabilisingstructure 3300 comprises a strap constructed from a laminate of a fabricpatient-contacting layer, a foam inner layer and a fabric outer layer.In one form, the foam is porous to allow moisture, (e.g., sweat), topass through the strap. In one form, the fabric outer layer comprisesloop material to engage with a hook material portion.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap that is extensible, e.g.resiliently extensible. For example the strap may be configured in useto be in tension, and to direct a force to draw a seal-forming structureinto sealing contact with a portion of a patient's face. In an examplethe strap may be configured as a tie.

In one form of the present technology, the positioning and stabilisingstructure comprises a first tie, the first tie being constructed andarranged so that in use at least a portion of an inferior edge thereofpasses superior to an otobasion superior of the patient's head andoverlays a portion of a parietal bone without overlaying the occipitalbone.

In one form of the present technology suitable for a nasal-only mask orfor a full-face mask, the positioning and stabilising structure includesa second tie, the second tie being constructed and arranged so that inuse at least a portion of a superior edge thereof passes inferior to anotobasion inferior of the patient's head and overlays or lies inferiorto the occipital bone of the patient's head.

In one form of the present technology suitable for a nasal-only mask orfor a full-face mask, the positioning and stabilising structure includesa third tie that is constructed and arranged to interconnect the firsttie and the second tie to reduce a tendency of the first tie and thesecond tie to move apart from one another.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap that is bendable and e.g.non-rigid. An advantage of this aspect is that the strap is morecomfortable for a patient to lie upon while the patient is sleeping.

In certain forms of the present technology, a positioning andstabilising structure 3300 comprises a strap constructed to bebreathable to allow moisture vapour to be transmitted through the strap,

In certain forms of the present technology, a system is providedcomprising more than one positioning and stabilizing structure 3300,each being configured to provide a retaining force to correspond to adifferent size and/or shape range. For example the system may compriseone form of positioning and stabilizing structure 3300 suitable for alarge sized head, but not a small sized head, and another. suitable fora small sized head, but not a large sized head.

FIGS. 21 and 22 show embodiments which are provided with connectors3310, e.g. magnetic connectors, for connection to a positioning andstabilising structure.

5.3.4.1 Frame

As shown in FIGS. 23 to 28 , a frame 3350 is coupled to the plenumchamber 3200 (e.g., as shown in FIGS. 7-19 ) and assists in maintainingthe therapeutically effective position of the seal-forming structure3100.

In some forms, the frame 3350 is constructed from a rigid or semi-rigidmaterial, and provides support to the seal-forming structure 3100 and/orthe plenum chamber 3200. For example, the frame 3350 may assist inmaintaining the shape of the seal-forming structure 3100 and/or theplenum chamber 3200 in order to reduce leaks of pressurized air as aresult of folding and/or creasing as the seal-forming structure 3100engages the patient's face.

In some forms, the frame 3350 provides at least one connection point3352, which may assist in indirectly connecting the headgear straps 3354to the plenum chamber 3200 and/or seal-forming structure 3100. Theconnection point 3352 may be a loop (e.g., with a fully formedperimeter) that receives a portion of the headgear straps 3354. Forexample, a length of a left superior headgear strap 3356 may be threadedthrough a first loop 3352 a, and pulled away from the plenum chamber3200 in order to apply tension through the left superior headgear strap3356. The left superior headgear strap 3356 may be folded against itselfand retained in the selected length (e.g., using Velcro, magnets,adhesives, etc.) in order to maintain the applied tension. Similar stepsmay be performed regarding adjusting the tension in the right superiorheadgear strap 3358 in a second loop 3352 b.

In some forms, each loop 3352 a, 3352 b may be oriented so that a forcevector applied by the respective superior headgear strap 3356, 3358 issubstantially perpendicular to a loop inner surface 3351, against whichthe superior headgear straps 3356, 3358 contact. As shown in FIG. 23 ,the right superior headgear strap 3358 engages the loop 3352 b insubstantially the center of the loop inner surface 3351. When the rightsuperior headgear strap 3358 is tightened, the force vector is appliedin a substantially straight direction, and not oblique relative to theloop inner surface 3351. This may improve the sealing of theseal-forming structure 3100, as the forces are directed along the arms3362, and not oblique relative to the arms 3362, which may require thesuperior headgear straps 3356, 3358 to be further tightened to receivethe same sealing effects (e.g., at the detriment to patient comfort),and/or may prevent the seal-forming structure 3100 from properlyengaging the patient's face (e.g., leading to leaks).

In one form, at least one of the loops 3352 a, 3352 b may not becompletely formed around an outer perimeter. In other words, the loops3352 a, 3352 b may be C-shaped and/or U-shaped. The left and/or rightsuperior headgear straps 3356, 3358 may be individually folded againstthemselves, and then inserted through into the respective loop 3352 a,3352 b. This may allow the patient to maintain the same lengthadjustment in the respective superior headgear strap 3356, 3358, whenthe seal-forming structure 3100 is being removed from thetherapeutically effective position.

In some forms, the frame 3350 includes a central portion 3360 that iscoupled to the plenum chamber 3200. The central portion 3360 may have anannular shape, and may have a profile that corresponds to the shape ofthe plenum chamber 3200 (e.g., approximating a positive domedcurvature).

In one form, a single size of the central portion 3360 may be used witha variety of sizes of plenum chambers 3200 and/or seal-formingstructures 3100. For example, the seal-forming structure 3100 may comein multiple sizes (e.g., small, medium, large, etc.) and/or shapes(e.g., narrow, wide, etc.) in order to better seal against patients witha variety of facial shapes. An engagement region of the central portion3360 may remain substantially the same regardless of the size of theplenum chamber 3200 and/or seal-forming structure 3100. Thus, thecentral portion 3360 may be coupled to a variety of shaped and/or sizedcushions, and provide substantially the same support.

In one form, the central portion 3360 may be removable coupled to theplenum chamber 3200. A patient may use the same frame 3350 with multipleplenum chambers 3200. This may be useful when the patient is firstbeginning the therapy, and is trying different sized plenum chambers3200, in order to find an appropriate fit. Removing the frame 3350 mayalso be helpful when cleaning the patient interface 3000, as thedifferent elements of the patient interface 3000 may be cleanedseparately, to help ensure a more thorough clean.

In some forms, the frame 3350 includes arms 3362 that extend away fromthe central portion 3360. The loops 3352 a, 3352 b are formed at ends ofthe arms 3362. In use, the arms 3362 may extend at least partially inthe posterior direction, which may position the loops 3352 a, 3352 bmore posterior than the plenum chamber 3200 and/or the seal-formingstructure 3100. The arms 3362 may also extend in the lateral direction(e.g., left or right respectively) so as to generally extend alongcontours of the patient's face.

In some forms, the arms 3362 engage a portion of the patient's facewhile the patient interface 3000 is worn by the patient. For example,the arms 3362 may contact the patient's cheeks. The arms 3362 may beshaped in order to correspond to the curvatures of a patient's face(e.g., extend in posterior and lateral directions).

In some forms, the arms 3362 may not substantially stretch as a resultof the tension applied by the respective headgear strap 3356, 3358 viathe respective loop 3352 a, 3352 b (e.g., the arms 3362 may berigidizers and/or may be inextensible). Tension may be transferred alongthe arm 3362 to the plenum chamber 3200 and/or seal-forming structure3100 in order to maintain the therapeutically effective pressure andlimit leaks from occurring.

In one form, the arms 3362 are constructed from a material that is moreflexible than the material used to construct the central portion 3360.The two materials may be molded together so that the frame 3350 isconstructed in an integral, one-piece construction. The arms 3362 mayhave some rigidity in order to assist in maintaining their shape.However, the arms 3362 may be bendable so that a patient may adjust theshape in order to correspond to their facial structure. Allowing apatient to adjust the shape of the arms 3362 may increase the comfortexperienced by the patient, which may increase patient compliance withthe therapy. In this way, the arms 3362 may bend or flex relative to thecentral portion 3360 (e.g., because of a cantilevered configuration),but may be unable to stretch further in the posterior direction (e.g.,because of its inextensibility). Additionally, the relatively flexiblematerial used to construct each of the arms 3362 may assist in reducingfacial markings, and increase patient comfort.

In one form, the arms 3362 and the central portion 3360 are constructedfrom the same material. This material provides enough flexibility inorder to permit shape adjustment, and also provides enough rigidity inorder to maintain the adjusted shape. The central portion 3360 may bemore rigid than the arms 3362 as a result of being coupled to the plenumchamber 3200. In addition or instead of, the central portion 3360 may bethicker than the arms 3362, which may also cause an increased rigidityof the central portion 3360. Each arm 3362 is formed as a cantileveredshape, so that the ends proximate to the respective loop 3352 a, 3352 bare unsupported. Additionally, the thickness of the frame 3350 maydecrease along the length of each arm 3362 in the direction of therespective loop 3352 a, 3352 b. This may provide each arm 3362 with theflexibility necessary to be bent and/or shaped in order to substantiallycorrespond to a shape of the patient's face (e.g., cheek). Decreasingthe width of each arm 3362 may also reduce cheek contact between therespective arm 3362 and the patient's cheek, which may improve patientcomfort. Decreasing the width along the length of each arm 3362 may alsoallow for greater flexibility proximate each respective loop 3352 a,3352 b.

In some forms, the fixed end of each arm 3362 may have a thickness ofbetween approximately 2 mm and approximately 7 mm. In some forms, thefixed end of each arm 3362 may have a thickness of between approximately2.5 mm and approximately 6 mm. In some forms, the fixed end of each arm3362 may have a thickness of between approximately 3 mm andapproximately 5 mm. In some forms, the fixed end of each arm 3362 mayhave a thickness of approximately 4 mm.

In some forms, the free end of each arm 3362 may have a thickness ofbetween approximately 0 mm and approximately 4 mm. In some forms, thefixed end of each arm 3362 may have a thickness of between approximately0.5 mm and approximately 3 mm. In some forms, the fixed end of each arm3362 may have a thickness of between approximately 1 mm andapproximately 2.5 mm. In some forms, the fixed end of each arm 3362 mayhave a thickness of approximately 2 mm.

In some forms, the frame 3350 further includes at least one secondaryconnection point 3364 that is spaced apart from the loops 3352 a, 3352b. The secondary connection point(s) 3364 provides an additionalconnection location, which may further assist in indirectly connectingthe headgear straps 3354 to the plenum chamber 3200 and/or seal-formingstructure 3100.

In certain forms, the frame 3350 includes two secondary connectionpoints 3364 (e.g., a left secondary connection point 3364 a, and a rightsecondary connection point 3364 b). The secondary connection points 3364a, 3364 b may be inferior to the loops 3352 a, 3352 b while the patientinterface 3000 is worn by the patient. The headgear straps 3354 mayfurther include a left inferior headgear straps 3366 and a rightinferior headgear strap 3368, each configured to couple to therespective secondary connection point 3364 a, 3364 b. The headgear 3354as a whole may then be able to provide a force to the superior andinferior regions of the seal-forming structure 3100 and/or the plenumchamber 3200.

In certain forms, the secondary connection points 3364 a, 3364 b areformed directly on the central portion 3360. The secondary connectionpoints 3364 a, 3364 b may be more anterior than the loops 3352 a, 3352 bwhile the patient interface 3000 is worn by the patient.

In certain forms, the secondary connection points 3364 a, 3364 b may beconstructed from a single component, which may assist in reducingtooling and/or manufacturing costs.

In certain forms, the left and/or right inferior headgear straps 3366,3368 are removably coupled to the respective secondary connection point3364 a, 3364 b. The secondary connection points 3364 a, 3364 b may bemagnetic, and a left and/or right inferior headgear straps 3366, 3368may be threaded through a magnet 3370 with an opposite polarity as thesecondary connection points 3364 a, 3364 b. The length of the leftand/or right inferior headgear straps 3366, 3368 may be adjusted byfolding the respective strap 3366, 3368 on itself (e.g., as done withthe left and/or right superior headgear straps 3356, 3358). Each magnet3370 may be removed from the respective secondary connection point 3364a, 3364 b, without changing the length adjustment of the left and/orright inferior headgear straps 3366, 3368. A patient may be able to donand/or doff the patient interface 3000 while only removing the magnets3370 from the respective secondary connection points 3364 a, 3364 b(e.g., without having to remove the left and/or right superior headgearstraps 3356, 3358 from the respective loops 3352 a, 3352 b).

As shown in FIG. 24 , the engagement region of the plenum chamber 3200may include a groove 3280. In the illustrated example, the groove 3280may be included on the oral portion 3201 of the plenum chamber 3200, andmay be radially outside of the central portion 3251. The central portion3360 of the frame 3350 may be positioned within the groove 3280. Theshape of the central portion 3360 may substantially correspond to theshape of the groove 3280, which may assist the patient in properlyorienting the frame 3350 with respect to the plenum chamber 3200 (e.g.,in examples where the frame 3350 is removably coupled to the plenumchamber 3200).

In some forms, the groove 3280 may have a completely formed perimeterwith a substantially annular shape. The perimeter may have substantiallythe same length in any sized cushion.

In some forms, the groove 3280 is recessed relative to a remainder ofthe outer surface of the plenum chamber 3200. The recessed groove 3280may not extend substantially into the plenum chamber 3200 and obstructthe patient's face. The groove 3280 may have substantially the samedepth throughout its perimeter.

In some forms, a width of the groove 3280 may be less than a width ofcentral portion 3360 of the frame 3350. The compliant nature of thecushion may allow the wider central portion 3360 to be received withinthe groove 3280. This may allow the central portion 3360 to couple tothe groove 3280 via a press fit, friction fit, and/or snap-fit. Theengagement between the groove 3280 and the central portion 3360 mayassist in providing rigidity to the plenum chamber 3200 and/or theseal-forming structure 3100, because the rigidity of the frame 3350(e.g., as compared to the plenum chamber 3200) may limit someflexibility of the plenum chamber 3200 alone.

In some forms, the cushion may be molded to the frame 3350 so that thegroove 3280 may be created during a molding process. The material of theplenum chamber 3200 (e.g., silicone) may be molded at least partiallyaround the central portion 3360 of the frame 3350, and may limit thecentral portion 3360 from being removed from the groove 3280.

As shown in FIG. 25 , the frame 3350 may be constructed from multiplepieces (e.g., each constructed from a different material). For example,the central portion may be constructed from a first material (e.g., hardplastic). The arms 3362 may be coupled to the central portion 3360(e.g., via glue, molding, etc.), and may be constructed from a secondmaterial (e.g., flexible plastic, foam, etc.) that is more flexible thanthe first material. A third material may be a magnetic material, and maybe coupled to the central portion 3360 (e.g., via an adhesive). Oncecoupled together, the arms 3362 may be able to similarly move as in theintegral, one-piece constructions described above.

As shown in FIGS. 26 and 27 , the frame 3350 may be constructed from asingle piece of material. For example, the frame 3350 may be constructedfrom a TPE material, like Hytrel. As described above, the material usedin constructing the frame 3350 may provide both rigidity and flexibilityto the frame 3350. The magnets 3370 may be overmolded (or otherwisecoupled to) the central portion 3360.

In some forms, the central portion 3360 includes openings or slots 3372,which may be formed on either lateral side of the central portion 3360.The slots 3372 may have a generally elongated shape (e.g., rectangular,elliptical, etc.), and may be completely formed within the boundary ofthe central portion 3360.

As shown in FIG. 27 , some forms of the central portion 3360 may includea tapered slot 3372. Specifically, an opening to the slot 3372 may bewider proximate a posterior surface of the central portion 3360 (e.g.,the surface in contact with the plenum chamber 3200). The opening to theslot 3372 may decrease uniformly toward the anterior surface of thecentral portion 3360.

FIG. 27 also illustrates that some forms of the arm 3362 a (or arm 3362b) may include an indent or scallop 3373. The scallop 3373 may be formedon an inner surface of the arm 3362 a, and may be positioned proximateto the patient's skin when the positioning and stabilizing structure3300 is worn by the patient. The scallop 3373 reduces the thicknessalong a portion of the arm 3362 a, and may decrease the likelihood ofdeveloping sink marks in the arm 3362 a during a manufacturing (e.g.,injection molding) process. The scallop 3373 may also result in lessmaterial being used to manufacture the arm 3362 a, which may lead tolower manufacturing times and/or lower manufacturing costs.

Returning to FIG. 26 , the plenum chamber 3200 may include projections3284 on the oral portion 3201. The projections may be elongated, and mayhave a similar shape to the slots 3372 (e.g., tapered). The projections3284 may be disposed within the groove 3280 so that they cooperate withthe frame 3350 during assembly. When the frame 3350 is being assembledto the plenum chamber 3200 (e.g., via a press fit, friction fit,snap-fit, etc.), the patient may align the projections 3284 with theslots 3372, so that the projections 3284 are received within the slots3372 in use. The wider openings of the slots 3372 proximate to theposterior surface may assist the patient in aligning each projection3284 within the respective slot 3372. The projections 3284 may beslightly wider than the anterior opening of each slot 3372, but are ableto be received within the slot because of the flexible properties of theplenum chamber 3200 (e.g., being constructed from a resilient materiallike silicone). The projections 3284 may slightly deform as they enterthe respective slot 3372 (e.g., as a result of the slot 3372 narrowing).Once the projections 3284 are through the slot 3372, the projections3284 may substantially return to their original shape. Specifically,ends of the projections 3284 may become wider than the anterior openingof the respective slot 3372. Thus, the frame 3350 may not be easilyremoved from the plenum chamber 3200. The patient may have to apply aforce to the frame 3350 in order to remove it from the groove 3280. Inother forms, the plenum chamber 3200 may be molded to the frame 3350,and the projections 3284 may result from the molding process in order topermanently retain the position of the frame 3350 relative to the plenumchamber 3200.

As shown in FIG. 28 , the frame 3350 may be shaped similarly to theframe in FIGS. 26 and 27 . In other words, the frame 3350 may beconstructed from a single material (e.g., with semi-rigid properties).The frame 3350 may be thicker proximate the central portion 3360, andthinner toward each respective loop 3352 a, 3352 b.

In some forms, the central portion 3360 of the frame 3350 may besubstantially solid throughout, and may not include slots 3372, and theplenum chamber 3200 may not include projections 3284 within the groove3280. Instead, the plenum chamber 3200 may include protrusions 3288disposed radially inside of the groove 3280. The protrusions 3288 may beraised from the rest of the anterior surface of the plenum chamber 3200.The protrusions 3288 may also extend at least partially in a radiallyoutward direction. In other words, the protrusions 3288 may extend atleast partially over the groove 3280 (e.g., the protrusions 3388 arespaced apart from the groove 3380).

While assembling a removable frame 3350 to the plenum chamber 3200, apatient may be required to position the frame 3350 so that it extendsinto the groove 3280, and underneath of the protrusions 3288. Once thecentral portion 3260 is positioned, the protrusions 3288 may assist inretaining the central portion 3360 in place. To decouple the frame 3350from the plenum chamber 3200, the patient may push on at least one ofthe protrusions 3288 (e.g., in a lateral direction toward the otherprotrusion 3288) so that the protrusion no longer extends over thegroove 3280. In other forms, the plenum chamber 3200 may be molded tothe frame 3350, the protrusions 3288 may prevent the central portion3360 from being removed.

In some forms, the frame 3350 of any of the examples described above maybe substantially flush with the outer surface of the plenum chamber 3200when positioned within the groove 3280. The depth of the groove 3280substantially corresponds to a thickness of the central portion 3360.Similarly, the shape of the central portion may substantiallyapproximate the shape of the cushion as described above. The resultingassembly may have a substantially uniform surface. This assists inmaintaining a low profile look of the patient interface 3000, becausethe frame 3350 is not projecting in front of the cushion where it mayobstruct the patient's line of sight.

5.3.5 Vent

In one form, the patient interface 3000 includes a vent 3400 constructedand arranged to allow for the washout of exhaled gases, e.g. carbondioxide.

In certain forms the vent 3400 is configured to allow a continuous ventflow from an interior of the plenum chamber 3200 to ambient whilst thepressure within the plenum chamber is positive with respect to ambient.The vent 3400 is configured such that the vent flow rate has a magnitudesufficient to reduce rebreathing of exhaled CO₂ by the patient whilemaintaining the therapeutic pressure in the plenum chamber in use.

One form of vent 3400 in accordance with the present technologycomprises a plurality of holes, for example, about 20 to about 80 holes,or about 40 to about 60 holes, or about 45 to about 55 holes.

The vent 3400 may be located in the plenum chamber 3200. Alternatively,the vent 3400 is located in a decoupling structure, e.g., a swivel.

While no vent structures are shown in FIGS. 7-18 , embodiments of thetechnology shown in FIGS. 7-18 may be provided with a suitable ventstructure, for example in the plenum chamber (one example of which isshown in FIG. 21 ).

5.3.6 Decoupling structure(s)

In one form the patient interface 3000 includes at least one decouplingstructure 3500, for example, a swivel or a ball and socket. In someexamples, the decoupling structure may be an elbow 3500 that isconnected (e.g., removably connected, permanently connected, etc.) tothe plenum chamber 3200 (e.g., a plenum chamber inlet port).

As shown in FIGS. 23-28 , the central portion 3360 of the frame 3350 hasan annular shape, so that a central region of the oral portion 3201 ofthe plenum chamber 3200 is not covered by the frame 3350. In someexamples, the oral portion 3201 includes an opening for receiving theelbow 3500. The opening may be significantly wider than the opening forreceiving the elbow 3500, so that the frame 3350 is completely spacedapart from the opening. In other words, there is a length between theinner edge of the central portion 3360 and the opening for receiving theelbow 3500. The arms 3362 a, 3362 b and the secondary connectionportions 3342 a, 3342 b are each spaced apart from the opening and theelbow 3500, so that the headgear straps 3358 do not interfere withmovement (e.g., rotation) of the elbow.

While not explicitly shown in the drawings of the plenum chamber shownin FIGS. 7-19 , those skilled in the art will appreciate that inpractice an elbow 3500 may be provided (e.g., as illustrated in FIG. 23), and allow connection of the interface to an air circuit 4170.

5.3.7 Connection Port

Connection port 3600 allows for connection (e.g., a removable connectionvia a snap-fit, a permanent connection, etc.) to the air circuit 4170.The patient interface 3000 may include two connection ports 3600, one oneither side of the plenum chamber 3200. Conduits may connect to theconnection ports 3600 in order to convey pressurized breathable gas tothe patient. In some forms, the conduits may be conduit headgear, andmay contact the patient's head. The conduits may extend toward the crownof the patient's head, where the decoupling structure 3500 is located.

5.3.8 Forehead Support

In one form, the patient interface 3000 includes a forehead support3700.

5.3.9 Anti-Asphyxia Valve

In one form, the patient interface 3000 includes an anti-asphyxia valve.

5.3.10 Ports

In one form of the present technology, a patient interface 3000 includesone or more ports that allow access to the volume within the plenumchamber 3200. In one form this allows a clinician to supplysupplementary oxygen. In one form, this allows for the directmeasurement of a property of gases within the plenum chamber 3200, suchas the pressure.

5.4 RPT Device

An RPT device 4000 in accordance with one aspect of the presenttechnology comprises mechanical, pneumatic, and/or electrical componentsand is configured to execute one or more algorithms 4300, such as any ofthe methods, in whole or in part, described herein. The RPT device 4000may be configured to generate a flow of air for delivery to a patient'sairways, such as to treat one or more of the respiratory conditionsdescribed elsewhere in the present document.

In one form, the RPT device 4000 is constructed and arranged to becapable of delivering a flow of air in a range of −20 L/min to +150L/min while maintaining a positive pressure of at least 6 cmH₂O, or atleast 10cmH₂O, or at least 20 cmH₂O.

The RPT device may have an external housing 4010, formed in two parts,an upper portion 4012 and a lower portion 4014. Furthermore, theexternal housing 4010 may include one or more panel(s) 4015. The RPTdevice 4000 comprises a chassis 4016 that supports one or more internalcomponents of the RPT device 4000. The RPT device 4000 may include ahandle 4018.

The pneumatic path of the RPT device 4000 may comprise one or more airpath items, e.g., an inlet air filter 4112, an inlet muffler 4122, apressure generator 4140 capable of supplying air at positive pressure(e.g., a blower 4142), an outlet muffler 4124 and one or moretransducers 4270, such as pressure sensors 4272 and flow rate sensors4274.

One or more of the air path items may be located within a removableunitary structure which will be referred to as a pneumatic block 4020.The pneumatic block 4020 may be located within the external housing4010. In one form a pneumatic block 4020 is supported by, or formed aspart of the chassis 4016.

The RPT device 4000 may have an electrical power supply 4210, one ormore input devices 4220, a central controller 4230, a therapy devicecontroller 4240, a pressure generator 4140, one or more protectioncircuits 4250, memory 4260, transducers 4270, data communicationinterface 4280 and one or more output devices 4290. Electricalcomponents 4200 may be mounted on a single Printed Circuit BoardAssembly (PCBA) 4202. In an alternative form, the RPT device 4000 mayinclude more than one PCBA 4202.

5.4.1.1 Air Filter(s)

An RPT device in accordance with one form of the present technology mayinclude an air filter 4110, or a plurality of air filters 4110.

In one form, an inlet air filter 4112 is located at the beginning of thepneumatic path upstream of a pressure generator 4140.

In one form, an outlet air filter 4114, for example an antibacterialfilter, is located between an outlet of the pneumatic block 4020 and apatient interface 3000 or 3800.

5.4.1.2 Muffler(s)

An RPT device in accordance with one form of the present technology mayinclude a muffler 4120, or a plurality of mufflers 4120.

In one form of the present technology, an inlet muffler 4122 is locatedin the pneumatic path upstream of a pressure generator 4140.

In one form of the present technology, an outlet muffler 4124 is locatedin the pneumatic path between the pressure generator 4140 and a patientinterface 3000 or 3800.

5.4.1.3 Pressure Generator

In one form of the present technology, a pressure generator 4140 forproducing a flow, or a supply, of air at positive pressure is acontrollable blower 4142. For example, the blower 4142 may include abrushless DC motor 4144 with one or more impellers. The impellers may belocated in a volute. The blower may be capable of delivering a supply ofair, for example at a rate of up to about 120 litres/minute, at apositive pressure in a range from about 4 cmH2O to about 20 cmH2O, or inother forms up to about 30 cmH2O when delivering respiratory pressuretherapy. The blower may be as described in any one of the followingpatents or patent applications the contents of which are incorporatedherein by reference in their entirety: U.S. Pat. Nos. 7,866,944;8,638,014; 8,636,479; and PCT Patent Application Publication No. WO2013/020167.

The pressure generator 4140 may be under the control of the therapydevice controller 4240.

In other forms, a pressure generator 4140 may be a piston-driven pump, apressure regulator connected to a high pressure source (e.g. compressedair reservoir), or a bellows.

5.4.1.4 Transducer(s)

Transducers may be internal of the RPT device, or external of the RPTdevice. External transducers may be located for example on or form partof the air circuit, e.g., the patient interface. External transducersmay be in the form of non-contact sensors such as a Doppler radarmovement sensor that transmit or transfer data to the RPT device.

In one form of the present technology, one or more transducers 4270 arelocated upstream and/or downstream of the pressure generator 4140. Theone or more transducers 4270 may be constructed and arranged to generatesignals representing properties of the flow of air such as a flow rate,a pressure or a temperature at that point in the pneumatic path.

In one form of the present technology, one or more transducers 4270 maybe located proximate to the patient interface 3000 or 3800.

In one form, a signal from a transducer 4270 may be filtered, such as bylow-pass, high-pass or band-pass filtering.

5.4.1.5 Anti-Spill Back Valve

In one form of the present technology, an anti-spill back valve 4160 islocated between the humidifier 5000 and the pneumatic block 4020. Theanti-spill back valve is constructed and arranged to reduce the riskthat water will flow upstream from the humidifier 5000, for example tothe motor 4144.

5.4.2 RPT Device Electrical Components

5.4.2.1 Power Supply

A power supply 4210 may be located internal or external of the externalhousing 4010 of the RPT device 4000.

In one form of the present technology, power supply 4210 provideselectrical power to the RPT device 4000 only. In another form of thepresent technology, power supply 4210 provides electrical power to bothRPT device 4000 and humidifier 5000.

5.4.3 RPT Device Algorithms

As mentioned above, in some forms of the present technology, the centralcontroller 4230 may be configured to implement one or more algorithms4300 expressed as computer programs stored in a non-transitory computerreadable storage medium, such as memory 4260. The algorithms 4300 aregenerally grouped into groups referred to as modules.

In other forms of the present technology, some portion or all of thealgorithms 4300 may be implemented by a controller of an external devicesuch as the local external device 4288 or the remote external device4286. In such forms, data representing the input signals and/orintermediate algorithm outputs necessary for the portion of thealgorithms 4300 to be executed at the external device may becommunicated to the external device via the local external communicationnetwork 4284 or the remote external communication network 4282. In suchforms, the portion of the algorithms 4300 to be executed at the externaldevice may be expressed as computer programs stored in a non-transitorycomputer readable storage medium accessible to the controller of theexternal device. Such programs configure the controller of the externaldevice to execute the portion of the algorithms 4300.

In such forms, the therapy parameters generated by the external devicevia the therapy engine module 4320 (if such forms part of the portion ofthe algorithms 4300 executed by the external device) may be communicatedto the central controller 4230 to be passed to the therapy controlmodule 4330.

5.5 Air Circuit

An air circuit 4170 in accordance with an aspect of the presenttechnology is a conduit or a tube constructed and arranged to allow, inuse, a flow of air to travel between two components such as RPT device4000 and the patient interface 3000.

In particular, the air circuit 4170 may be in fluid connection with theoutlet of the pneumatic block 4020 and the patient interface. The aircircuit may be referred to as an air delivery tube. In some cases theremay be separate limbs of the circuit for inhalation and exhalation. Inother cases a single limb is used.

In some forms, the air circuit 4170 may comprise one or more heatingelements configured to heat air in the air circuit, for example tomaintain or raise the temperature of the air. The heating element may bein a form of a heated wire circuit, and may comprise one or moretransducers, such as temperature sensors. In one form, the heated wirecircuit may be helically wound around the axis of the air circuit 4170.The heating element may be in communication with a controller such as acentral controller 4230. One example of an air circuit 4170 comprising aheated wire circuit is described in U.S. Pat. No. 8,733,349, which isincorporated herewithin in its entirety by reference.

5.5.1 Supplementary Gas Delivery

In one form of the present technology, supplementary gas, e.g. oxygen,4180 is delivered to one or more points in the pneumatic path, such asupstream of the pneumatic block 4020, to the air circuit 4170, and/or tothe patient interface 3000.

5.6 Humidifier

5.6.1 Humidifier Overview

In one form of the present technology there is provided a humidifier5000 (e.g. as shown in FIG. 5A) to change the absolute humidity of airor gas for delivery to a patient relative to ambient air. Typically, thehumidifier 5000 is used to increase the absolute humidity and increasethe temperature of the flow of air (relative to ambient air) beforedelivery to the patient's airways.

The humidifier 5000 may comprise a humidifier reservoir 5110, ahumidifier inlet 5002 to receive a flow of air, and a humidifier outlet5004 to deliver a humidified flow of air. In some forms, as shown inFIG. 5A and FIG. 5B, an inlet and an outlet of the humidifier reservoir5110 may be the humidifier inlet 5002 and the humidifier outlet 5004respectively. The humidifier 5000 may further comprise a humidifier base5006, which may be adapted to receive the humidifier reservoir 5110 andcomprise a heating element 5240.

5.6.2 Humidifier Components

5.6.2.1 Water Reservoir

According to one arrangement, the humidifier 5000 may comprise a waterreservoir 5110 configured to hold, or retain, a volume of liquid (e.g.water) to be evaporated for humidification of the flow of air. The waterreservoir 5110 may be configured to hold a predetermined maximum volumeof water in order to provide adequate humidification for at least theduration of a respiratory therapy session, such as one evening of sleep.Typically, the reservoir 5110 is configured to hold several hundredmillilitres of water, e.g. 300 millilitres (ml), 325 ml, 350 ml or 400ml. In other forms, the humidifier 5000 may be configured to receive asupply of water from an external water source such as a building's watersupply system.

According to one aspect, the water reservoir 5110 is configured to addhumidity to a flow of air from the RPT device 4000 as the flow of airtravels therethrough. In one form, the water reservoir 5110 may beconfigured to encourage the flow of air to travel in a tortuous paththrough the reservoir 5110 while in contact with the volume of watertherein.

According to one form, the reservoir 5110 may be removable from thehumidifier 5000, for example in a lateral direction as shown in FIG. 5Aand FIG. 5B.

The reservoir 5110 may also be configured to discourage egress of liquidtherefrom, such as when the reservoir 5110 is displaced and/or rotatedfrom its normal, working orientation, such as through any aperturesand/or in between its sub-components. As the flow of air to behumidified by the humidifier 5000 is typically pressurised, thereservoir 5110 may also be configured to prevent losses in pneumaticpressure through leak and/or flow impedance.

5.6.2.2 Conductive Portion

According to one arrangement, the reservoir 5110 comprises a conductiveportion 5120 configured to allow efficient transfer of heat from theheating element 5240 to the volume of liquid in the reservoir 5110. Inone form, the conductive portion 5120 may be arranged as a plate,although other shapes may also be suitable. All or a part of theconductive portion 5120 may be made of a thermally conductive materialsuch as aluminium (e.g. approximately 2 mm thick, such as 1 mm, 1.5 mm,2.5 mm or 3 mm), another heat conducting metal or some plastics. In somecases, suitable heat conductivity may be achieved with less conductivematerials of suitable geometry.

5.6.2.3 Humidifier Reservoir Dock

In one form, the humidifier 5000 may comprise a humidifier reservoirdock 5130 (as shown in FIG. 5B) configured to receive the humidifierreservoir 5110. In some arrangements, the humidifier reservoir dock 5130may comprise a locking feature such as a locking lever 5135 configuredto retain the reservoir 5110 in the humidifier reservoir dock 5130.

5.6.2.4 Water Level Indicator

The humidifier reservoir 5110 may comprise a water level indicator 5150as shown in FIG. 5A-5B. In some forms, the water level indicator 5150may provide one or more indications to a user such as the patient 1000or a care giver regarding a quantity of the volume of water in thehumidifier reservoir 5110. The one or more indications provided by thewater level indicator 5150 may include an indication of a maximum,predetermined volume of water, any portions thereof, such as 25%, 50% or75% or volumes such as 200 ml, 300 ml or 400 ml.

5.7 Breathing Waveforms

FIG. 6 shows a model typical breath waveform of a person while sleeping.The horizontal axis is time, and the vertical axis is respiratory flowrate. While the parameter values may vary, a typical breath may have thefollowing approximate values: tidal volume Vt 0.5 L, inhalation time Ti1.6 s, peak inspiratory flow rate Qpeak 0.4 L/s, exhalation time Te 2.4s, peak expiratory flow rate Qpeak −0.5 L/s. The total duration of thebreath, Ttot, is about 4 s. The person typically breathes at a rate ofabout 15 breaths per minute (BPM), with Ventilation Vent about 7.5L/min. A typical duty cycle, the ratio of Ti to Ttot, is about 40%.

5.8 Respiratory Therapy Modes

Various respiratory therapy modes may be implemented by the disclosedrespiratory therapy system including CPAP therapy and bi-level therapy.

5.9 GLOSSARY

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

5.9.1 General

Air: In certain forms of the present technology, air may be taken tomean atmospheric air, and in other forms of the present technology airmay be taken to mean some other combination of breathable gases, e.g.atmospheric air enriched with oxygen.

Ambient: In certain forms of the present technology, the term ambientwill be taken to mean (i) external of the treatment system or patient,and (ii) immediately surrounding the treatment system or patient.

For example, ambient humidity with respect to a humidifier may be thehumidity of air immediately surrounding the humidifier, e.g. thehumidity in the room where a patient is sleeping. Such ambient humiditymay be different to the humidity outside the room where a patient issleeping.

In another example, ambient pressure may be the pressure immediatelysurrounding or external to the body.

In certain forms, ambient (e.g., acoustic) noise may be considered to bethe background noise level in the room where a patient is located, otherthan for example, noise generated by an RPT device or emanating from amask or patient interface. Ambient noise may be generated by sourcesoutside the room.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in whichthe treatment pressure is automatically adjustable, e.g. from breath tobreath, between minimum and maximum limits, depending on the presence orabsence of indications of SDB events.

Continuous Positive Airway Pressure (CPAP) therapy: Respiratory pressuretherapy in which the treatment pressure is approximately constantthrough a respiratory cycle of a patient. In some forms, the pressure atthe entrance to the airways will be slightly higher during exhalation,and slightly lower during inhalation. In some forms, the pressure willvary between different respiratory cycles of the patient, for example,being increased in response to detection of indications of partial upperairway obstruction, and decreased in the absence of indications ofpartial upper airway obstruction.

Flow rate: The volume (or mass) of air delivered per unit time. Flowrate may refer to an instantaneous quantity. In some cases, a referenceto flow rate will be a reference to a scalar quantity, namely a quantityhaving magnitude only. In other cases, a reference to flow rate will bea reference to a vector quantity, namely a quantity having bothmagnitude and direction. Flow rate may be given the symbol Q. ‘Flowrate’ is sometimes shortened to simply ‘flow’ or ‘airflow’.

In the example of patient respiration, a flow rate may be nominallypositive for the inspiratory portion of a breathing cycle of a patient,and hence negative for the expiratory portion of the breathing cycle ofa patient. Device flow rate, Qd, is the flow rate of air leaving the RPTdevice. Total flow rate, Qt, is the flow rate of air and anysupplementary gas reaching the patient interface via the air circuit.Vent flow rate, Qv, is the flow rate of air leaving a vent to allowwashout of exhaled gases. Leak flow rate, Ql, is the flow rate of leakfrom a patient interface system or elsewhere. Respiratory flow rate, Qr,is the flow rate of air that is received into the patient's respiratorysystem.

Flow therapy: Respiratory therapy comprising the delivery of a flow ofair to an entrance to the airways at a controlled flow rate referred toas the treatment flow rate that is typically positive throughout thepatient's breathing cycle.

Humidifier: The word humidifier will be taken to mean a humidifyingapparatus constructed and arranged, or configured with a physicalstructure to be capable of providing a therapeutically beneficial amountof water (H₂O) vapour to a flow of air to ameliorate a medicalrespiratory condition of a patient.

Leak: The word leak will be taken to be an unintended flow of air. Inone example, leak may occur as the result of an incomplete seal betweena mask and a patient's face. In another example leak may occur in aswivel elbow to the ambient.

Noise, conducted (acoustic): Conducted noise in the present documentrefers to noise which is carried to the patient by the pneumatic path,such as the air circuit and the patient interface as well as the airtherein. In one form, conducted noise may be quantified by measuringsound pressure levels at the end of an air circuit.

Noise, radiated (acoustic): Radiated noise in the present documentrefers to noise which is carried to the patient by the ambient air. Inone form, radiated noise may be quantified by measuring soundpower/pressure levels of the object in question according to ISO 3744.

Noise, vent (acoustic): Vent noise in the present document refers tonoise which is generated by the flow of air through any vents such asvent holes of the patient interface.

Patient: A person, whether or not they are suffering from a respiratorycondition.

Pressure: Force per unit area. Pressure may be expressed in a range ofunits, including cmH₂O, g-f/cm² and hectopascal. 1 cmH₂O is equal to 1g-f/cm² and is approximately 0.98 hectopascal (1 hectopascal=100 Pa=100N/m²=1 millibar 0.001 atm). In this specification, unless otherwisestated, pressure is given in units of cmH₂O.

The pressure in the patient interface is given the symbol Pm, while thetreatment pressure, which represents a target value to be achieved bythe interface pressure Pm at the current instant of time, is given thesymbol Pt.

Respiratory Pressure Therapy (RPT): The application of a supply of airto an entrance to the airways at a treatment pressure that is typicallypositive with respect to atmosphere.

Ventilator: A mechanical device that provides pressure support to apatient to perform some or all of the work of breathing.

5.9.1.1 Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Corning.Another manufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, an exemplary form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using ASTMD2240.

Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.

5.9.1.2 Mechanical Properties

Resilience: Ability of a material to absorb energy when deformedelastically and to release the energy upon unloading.

Resilient: Will release substantially all of the energy when unloaded.Includes e.g. certain silicones, and thermoplastic elastomers.

Hardness: The ability of a material per se to resist deformation (e.g.described by a Young's Modulus, or an indentation hardness scalemeasured on a standardised sample size).

-   -   ‘Soft’ materials may include silicone or thermo-plastic        elastomer (TPE), and may, e.g. readily deform under finger        pressure.    -   ‘Hard’ materials may include polycarbonate, polypropylene, steel        or aluminium, and may not e.g. readily deform under finger        pressure.

Stiffness (or rigidity) of a structure or component: The ability of thestructure or component to resist deformation in response to an appliedload. The load may be a force or a moment, e.g. compression, tension,bending or torsion. The structure or component may offer differentresistances in different directions. The inverse of stiffness isflexibility.

Floppy structure or component: A structure or component that will changeshape, e.g. bend, when caused to support its own weight, within arelatively short period of time such as 1 second.

Rigid structure or component: A structure or component that will notsubstantially change shape when subject to the loads typicallyencountered in use. An example of such a use may be setting up andmaintaining a patient interface in sealing relationship with an entranceto a patient's airways, e.g. at a load of approximately 20 to 30 cmH₂Opressure.

As an example, an I-beam may comprise a different bending stiffness(resistance to a bending load) in a first direction in comparison to asecond, orthogonal direction. In another example, a structure orcomponent may be floppy in a first direction and rigid in a seconddirection.

5.9.2 Respiratory Cycle

Apnea: According to some definitions, an apnea is said to have occurredwhen flow falls below a predetermined threshold for a duration, e.g. 10seconds. An obstructive apnea will be said to have occurred when,despite patient effort, some obstruction of the airway does not allowair to flow. A central apnea will be said to have occurred when an apneais detected that is due to a reduction in breathing effort, or theabsence of breathing effort, despite the airway being patent. A mixedapnea occurs when a reduction or absence of breathing effort coincideswith an obstructed airway.

Breathing rate: The rate of spontaneous respiration of a patient,usually measured in breaths per minute.

Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

Effort (breathing): The work done by a spontaneously breathing personattempting to breathe.

Expiratory portion of a breathing cycle: The period from the start ofexpiratory flow to the start of inspiratory flow.

Flow limitation: Flow limitation will be taken to be the state ofaffairs in a patient's respiration where an increase in effort by thepatient does not give rise to a corresponding increase in flow. Whereflow limitation occurs during an inspiratory portion of the breathingcycle it may be described as inspiratory flow limitation. Where flowlimitation occurs during an expiratory portion of the breathing cycle itmay be described as expiratory flow limitation.

Types of flow limited inspiratory waveforms:

-   -   (i) Flattened: Having a rise followed by a relatively flat        portion, followed by a fall.    -   (ii) M-shaped: Having two local peaks, one at the leading edge,        and one at the trailing edge, and a relatively flat portion        between the two peaks.    -   (iii) Chair-shaped: Having a single local peak, the peak being        at the leading edge, followed by a relatively flat portion.    -   (iv) Reverse-chair shaped: Having a relatively flat portion        followed by single local peak, the peak being at the trailing        edge.

Hypopnea: According to some definitions, a hypopnea is taken to be areduction in flow, but not a cessation of flow. In one form, a hypopneamay be said to have occurred when there is a reduction in flow below athreshold rate for a duration. A central hypopnea will be said to haveoccurred when a hypopnea is detected that is due to a reduction inbreathing effort. In one form in adults, either of the following may beregarded as being hypopneas:

-   -   (i) a 30% reduction in patient breathing for at least 10 seconds        plus an associated 4% desaturation; or    -   (ii) a reduction in patient breathing (but less than 50%) for at        least 10 seconds, with an associated desaturation of at least 3%        or an arousal.

Hyperpnea: An increase in flow to a level higher than normal.

Inspiratory portion of a breathing cycle: The period from the start ofinspiratory flow to the start of expiratory flow will be taken to be theinspiratory portion of a breathing cycle.

Patency (airway): The degree of the airway being open, or the extent towhich the airway is open. A patent airway is open. Airway patency may bequantified, for example with a value of one (1) being patent, and avalue of zero (0), being closed (obstructed).

Positive End-Expiratory Pressure (PEEP): The pressure above atmospherein the lungs that exists at the end of expiration.

Peak flow rate (Qpeak): The maximum value of flow rate during theinspiratory portion of the respiratory flow waveform.

Respiratory flow rate, patient airflow rate, respiratory airflow rate(Qr): These terms may be understood to refer to the RPT device'sestimate of respiratory flow rate, as opposed to “true respiratory flowrate” or “true respiratory flow rate”, which is the actual respiratoryflow rate experienced by the patient, usually expressed in litres perminute.

Tidal volume (Vt): The volume of air inhaled or exhaled during normalbreathing, when extra effort is not applied. In principle theinspiratory volume Vi (the volume of air inhaled) is equal to theexpiratory volume Ve (the volume of air exhaled), and therefore a singletidal volume Vt may be defined as equal to either quantity. In practicethe tidal volume Vt is estimated as some combination, e.g. the mean, ofthe inspiratory volume Vi and the expiratory volume Ve.

(inhalation) Time (Ti): The duration of the inspiratory portion of therespiratory flow rate waveform.

(exhalation) Time (Te): The duration of the expiratory portion of therespiratory flow rate waveform.

(total) Time (Ttot): The total duration between the start of oneinspiratory portion of a respiratory flow rate waveform and the start ofthe following inspiratory portion of the respiratory flow rate waveform.

Typical recent ventilation: The value of ventilation around which recentvalues of ventilation Vent over some predetermined timescale tend tocluster, that is, a measure of the central tendency of the recent valuesof ventilation.

Upper airway obstruction (UAO): includes both partial and total upperairway obstruction. This may be associated with a state of flowlimitation, in which the flow rate increases only slightly or may evendecrease as the pressure difference across the upper airway increases(Starling resistor behaviour).

Ventilation (Vent): A measure of a rate of gas being exchanged by thepatient's respiratory system. Measures of ventilation may include one orboth of inspiratory and expiratory flow, per unit time. When expressedas a volume per minute, this quantity is often referred to as “minuteventilation”. Minute ventilation is sometimes given simply as a volume,understood to be the volume per minute.

5.9.3 Ventilation

Adaptive Servo-Ventilator (ASV): A servo-ventilator that has achangeable, rather than fixed target ventilation. The changeable targetventilation may be learned from some characteristic of the patient, forexample, a respiratory characteristic of the patient.

Backup rate: A parameter of a ventilator that establishes the minimumbreathing rate (typically in number of breaths per minute) that theventilator will deliver to the patient, if not triggered by spontaneousrespiratory effort.

Cycled: The termination of a ventilator's inspiratory phase. When aventilator delivers a breath to a spontaneously breathing patient, atthe end of the inspiratory portion of the breathing cycle, theventilator is said to be cycled to stop delivering the breath.

Expiratory positive airway pressure (EPAP): a base pressure, to which apressure varying within the breath is added to produce the desiredinterface pressure which the ventilator will attempt to achieve at agiven time.

End expiratory pressure (EEP): Desired interface pressure which theventilator will attempt to achieve at the end of the expiratory portionof the breath. If the pressure waveform template Π(Φ) is zero-valued atthe end of expiration, i.e. Π(Φ)=0 when Φ=1, the EEP is equal to theEPAP.

Inspiratory positive airway pressure (IPAP): Maximum desired interfacepressure which the ventilator will attempt to achieve during theinspiratory portion of the breath.

Pressure support: A number that is indicative of the increase inpressure during ventilator inspiration over that during ventilatorexpiration, and generally means the difference in pressure between themaximum value during inspiration and the base pressure (e.g.,PS=IPAP−EPAP). In some contexts pressure support means the differencewhich the ventilator aims to achieve, rather than what it actuallyachieves.

Servo-ventilator: A ventilator that measures patient ventilation, has atarget ventilation, and which adjusts the level of pressure support tobring the patient ventilation towards the target ventilation.

Spontaneous/Timed (S/T): A mode of a ventilator or other device thatattempts to detect the initiation of a breath of a spontaneouslybreathing patient. If however, the device is unable to detect a breathwithin a predetermined period of time, the device will automaticallyinitiate delivery of the breath.

Swing: Equivalent term to pressure support.

Triggered: When a ventilator delivers a breath of air to a spontaneouslybreathing patient, it is said to be triggered to do so at the initiationof the respiratory portion of the breathing cycle by the patient'sefforts.

5.9.4 Anatomy

5.9.4.1 Anatomy of the Face

Ala: the external outer wall or “wing” of each nostril (plural: alar)

Alare: The most lateral point on the nasal ala.

Alar curvature (or alar crest) point: The most posterior point in thecurved base line of each ala, found in the crease formed by the union ofthe ala with the cheek.

Auricle: The whole external visible part of the ear.

(nose) Bony framework: The bony framework of the nose comprises thenasal bones, the frontal process of the maxillae and the nasal part ofthe frontal bone.

(nose) Cartilaginous framework: The cartilaginous framework of the nosecomprises the septal, lateral, major and minor cartilages.

Columella: the strip of skin that separates the nares and which runsfrom the pronasale to the upper lip.

Columella angle: The angle between the line drawn through the midpointof the nostril aperture and a line drawn perpendicular to the Frankforthorizontal while intersecting subnasale.

Frankfort horizontal plane: A line extending from the most inferiorpoint of the orbital margin to the left tragion. The tragion is thedeepest point in the notch superior to the tragus of the auricle.

Glabella: Located on the soft tissue, the most prominent point in themidsagittal plane of the forehead.

Lateral nasal cartilage: A generally triangular plate of cartilage. Itssuperior margin is attached to the nasal bone and frontal process of themaxilla, and its inferior margin is connected to the greater alarcartilage.

Lip, lower (labrale inferius):

Lip, upper (labrale superius):

Greater alar cartilage: A plate of cartilage lying below the lateralnasal cartilage. It is curved around the anterior part of the naris. Itsposterior end is connected to the frontal process of the maxilla by atough fibrous membrane containing three or four minor cartilages of theala.

Nares (Nostrils): Approximately ellipsoidal apertures forming theentrance to the nasal cavity. The singular form of nares is naris(nostril). The nares are separated by the nasal septum.

Naso-labial sulcus or Naso-labial fold: The skin fold or groove thatruns from each side of the nose to the corners of the mouth, separatingthe cheeks from the upper lip.

Naso-labial angle: The angle between the columella and the upper lip,while intersecting subnasale.

Otobasion inferior: The lowest point of attachment of the auricle to theskin of the face.

Otobasion superior: The highest point of attachment of the auricle tothe skin of the face.

Pronasale: the most protruded point or tip of the nose, which can beidentified in lateral view of the rest of the portion of the head.

Philtrum: the midline groove that runs from lower border of the nasalseptum to the top of the lip in the upper lip region.

Pogonion: Located on the soft tissue, the most anterior midpoint of thechin.

Ridge (nasal): The nasal ridge is the midline prominence of the nose,extending from the Sellion to the Pronasale.

Sagittal plane: A vertical plane that passes from anterior (front) toposterior (rear). The midsagittal plane is a sagittal plane that dividesthe body into right and left halves.

Sellion: Located on the soft tissue, the most concave point overlyingthe area of the frontonasal suture.

Septal cartilage (nasal): The nasal septal cartilage forms part of theseptum and divides the front part of the nasal cavity.

Subalare: The point at the lower margin of the alar base, where the alarbase joins with the skin of the superior (upper) lip.

Subnasal point: Located on the soft tissue, the point at which thecolumella merges with the upper lip in the midsagittal plane.

Supramenton: The point of greatest concavity in the midline of the lowerlip between labrale inferius and soft tissue pogonion

5.9.4.2 Anatomy of the Skull

Frontal bone: The frontal bone includes a large vertical portion, thesquama frontalis, corresponding to the region known as the forehead.

Mandible: The mandible forms the lower jaw. The mental protuberance isthe bony protuberance of the jaw that forms the chin.

Maxilla: The maxilla forms the upper jaw and is located above themandible and below the orbits. The frontal process of the maxillaprojects upwards by the side of the nose, and forms part of its lateralboundary.

Nasal bones: The nasal bones are two small oblong bones, varying in sizeand form in different individuals; they are placed side by side at themiddle and upper part of the face, and form, by their junction, the“bridge” of the nose.

Nasion: The intersection of the frontal bone and the two nasal bones, adepressed area directly between the eyes and superior to the bridge ofthe nose.

Occipital bone: The occipital bone is situated at the back and lowerpart of the cranium. It includes an oval aperture, the foramen magnum,through which the cranial cavity communicates with the vertebral canal.The curved plate behind the foramen magnum is the squama occipitalis.

Orbit: The bony cavity in the skull to contain the eyeball.

Parietal bones: The parietal bones are the bones that, when joinedtogether, form the roof and sides of the cranium.

Temporal bones: The temporal bones are situated on the bases and sidesof the skull, and support that part of the face known as the temple.

Zygomatic bones: The face includes two zygomatic bones, located in theupper and lateral parts of the face and forming the prominence of thecheek.

5.9.4.3 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

5.9.5 Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: An elbow is an example of a structure that directs an axis offlow of air travelling therethrough to change direction through anangle. In one form, the angle may be approximately 90 degrees. Inanother form, the angle may be more, or less than 90 degrees. The elbowmay have an approximately circular cross-section. In another form theelbow may have an oval or a rectangular cross-section. In certain formsan elbow may be rotatable with respect to a mating component, e.g. about360 degrees. In certain forms an elbow may be removable from a matingcomponent, e.g. via a snap connection. In certain forms, an elbow may beassembled to a mating component via a one-time snap during manufacture,but not removable by a patient.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Headgear: Headgear will be taken to mean a form of positioning andstabilizing structure designed for use on a head. For example theheadgear may comprise a collection of one or more struts, ties andstiffeners configured to locate and retain a patient interface inposition on a patient's face for delivery of respiratory therapy. Someties are formed of a soft, flexible, elastic material such as alaminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a mask plenum chamber will be taken to mean a portion ofa patient interface having walls at least partially enclosing a volumeof space, the volume having air therein pressurised above atmosphericpressure in use. A shell may form part of the walls of a mask plenumchamber.

Seal: May be a noun form (“a seal”) which refers to a structure, or averb form (“to seal”) which refers to the effect. Two elements may beconstructed and/or arranged to ‘seal’ or to effect ‘sealing’therebetween without requiring a separate ‘seal’ element per se.

Shell: A shell will be taken to mean a curved, relatively thin structurehaving some bending, tensile and compressive stiffness. For example, acurved structural wall of a mask may be a shell. In some forms a shellor portions of a shell, may not be rigid. In some forms, a shell may befaceted. In some forms a shell may be airtight. In some forms a shellmay not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel (noun): A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. There may be little orno leak flow of air from the swivel in use.

Tie (noun): A structure designed to resist tension.

Vent: (noun): A structure that allows a flow of air from an interior ofthe mask, or conduit, to ambient air for clinically effective washout ofexhaled gases. For example, a clinically effective washout may involve aflow rate of about 10 litres per minute to about 100 litres per minute,depending on the mask design and treatment pressure.

5.9.6 Shape of Structures

Products in accordance with the present technology may comprise one ormore three-dimensional mechanical structures, for example a mask cushionor an impeller. The three-dimensional structures may be bounded bytwo-dimensional surfaces. These surfaces may be distinguished using alabel to describe an associated surface orientation, location, function,or some other characteristic. For example a structure may comprise oneor more of an anterior surface, a posterior surface, an interior surfaceand an exterior surface. In another example, a seal-forming structuremay comprise a face-contacting (e.g. outer) surface, and a separatenon-face-contacting (e.g. underside or inner) surface. In anotherexample, a structure may comprise a first surface and a second surface.

To facilitate describing the shape of the three-dimensional structuresand the surfaces, we first consider a cross-section through a surface ofthe structure at a point, p. See FIG. 3B to FIG. 3F, which illustrateexamples of cross-sections at point p on a surface, and the resultingplane curves. FIGS. 3B to 3F also illustrate an outward normal vector atp. The outward normal vector at p points away from the surface. In someexamples we describe the surface from the point of view of an imaginarysmall person standing upright on the surface.

5.9.6.1 Curvature in One Dimension

The curvature of a plane curve at p may be described as having a sign(e.g. positive, negative) and a magnitude (e.g. 1/radius of a circlethat just touches the curve at p).

Positive curvature: If the curve at p turns towards the outward normal,the curvature at that point will be taken to be positive (if theimaginary small person leaves the point p they must walk uphill). SeeFIG. 3B (relatively large positive curvature compared to FIG. 3C) andFIG. 3C (relatively small positive curvature compared to FIG. 3B). Suchcurves are often referred to as concave.

Zero curvature: If the curve at p is a straight line, the curvature willbe taken to be zero (if the imaginary small person leaves the point p,they can walk on a level, neither up nor down). See FIG. 3D.

Negative curvature: If the curve at p turns away from the outwardnormal, the curvature in that direction at that point will be taken tobe negative (if the imaginary small person leaves the point p they mustwalk downhill). See FIG. 3E (relatively small negative curvaturecompared to FIG. 3F) and FIG. 3F (relatively large negative curvaturecompared to FIG. 3E). Such curves are often referred to as convex.

5.9.6.2 Curvature of Two Dimensional Surfaces

A description of the shape at a given point on a two-dimensional surfacein accordance with the present technology may include multiple normalcross-sections. The multiple cross-sections may cut the surface in aplane that includes the outward normal (a “normal plane”), and eachcross-section may be taken in a different direction. Each cross-sectionresults in a plane curve with a corresponding curvature. The differentcurvatures at that point may have the same sign, or a different sign.Each of the curvatures at that point has a magnitude, e.g. relativelysmall. The plane curves in FIGS. 3B to 3F could be examples of suchmultiple cross-sections at a particular point.

Principal curvatures and directions: The directions of the normal planeswhere the curvature of the curve takes its maximum and minimum valuesare called the principal directions. In the examples of FIG. 3B to FIG.3F, the maximum curvature occurs in FIG. 3B, and the minimum occurs inFIG. 3F, hence FIG. 3B and FIG. 3F are cross sections in the principaldirections. The principal curvatures atp are the curvatures in theprincipal directions.

Region of a surface: A connected set of points on a surface. The set ofpoints in a region may have similar characteristics, e.g. curvatures orsigns.

Saddle region: A region where at each point, the principal curvatureshave opposite signs, that is, one is positive, and the other is negative(depending on the direction to which the imaginary person turns, theymay walk uphill or downhill).

Dome region: A region where at each point the principal curvatures havethe same sign, e.g. both positive (a “concave dome”) or both negative (a“convex dome”).

Cylindrical region: A region where one principal curvature is zero (or,for example, zero within manufacturing tolerances) and the otherprincipal curvature is non-zero.

Planar region: A region of a surface where both of the principalcurvatures are zero (or, for example, zero within manufacturingtolerances).

Edge of a surface: A boundary or limit of a surface or region.

Path: In certain forms of the present technology, ‘path’ will be takento mean a path in the mathematical—topological sense, e.g. a continuousspace curve from f(0) to f(1) on a surface. In certain forms of thepresent technology, a ‘path’ may be described as a route or course,including e.g. a set of points on a surface. (The path for the imaginaryperson is where they walk on the surface, and is analogous to a gardenpath).

Path length: In certain forms of the present technology, ‘path length’will be taken to mean the distance along the surface from f(0) to f(1),that is, the distance along the path on the surface. There may be morethan one path between two points on a surface and such paths may havedifferent path lengths. (The path length for the imaginary person wouldbe the distance they have to walk on the surface along the path).

Straight-line distance: The straight-line distance is the distancebetween two points on a surface, but without regard to the surface. Onplanar regions, there would be a path on the surface having the samepath length as the straight-line distance between two points on thesurface. On non-planar surfaces, there may be no paths having the samepath length as the straight-line distance between two points. (For theimaginary person, the straight-line distance would correspond to thedistance ‘as the crow flies’.)

5.9.6.3 Space Curves

Space curves: Unlike a plane curve, a space curve does not necessarilylie in any particular plane. A space curve may be closed, that is,having no endpoints. A space curve may be considered to be aone-dimensional piece of three-dimensional space. An imaginary personwalking on a strand of the DNA helix walks along a space curve. Atypical human left ear comprises a helix, which is a left-hand helix,see FIG. 3Q. A typical human right ear comprises a helix, which is aright-hand helix, see FIG. 3R. FIG. 3S shows a right-hand helix. Theedge of a structure, e.g. the edge of a membrane or impeller, may followa space curve. In general, a space curve may be described by a curvatureand a torsion at each point on the space curve. Torsion is a measure ofhow the curve turns out of a plane. Torsion has a sign and a magnitude.The torsion at a point on a space curve may be characterised withreference to the tangent, normal and binormal vectors at that point.

Tangent unit vector (or unit tangent vector): For each point on a curve,a vector at the point specifies a direction from that point, as well asa magnitude. A tangent unit vector is a unit vector pointing in the samedirection as the curve at that point. If an imaginary person were flyingalong the curve and fell off her vehicle at a particular point, thedirection of the tangent vector is the direction she would betravelling.

Unit normal vector: As the imaginary person moves along the curve, thistangent vector itself changes. The unit vector pointing in the samedirection that the tangent vector is changing is called the unitprincipal normal vector. It is perpendicular to the tangent vector.

Binormal unit vector: The binormal unit vector is perpendicular to boththe tangent vector and the principal normal vector. Its direction may bedetermined by a right-hand rule (see e.g. FIG. 3P), or alternatively bya left-hand rule (FIG. 3O).

Osculating plane: The plane containing the unit tangent vector and theunit principal normal vector. See FIGS. 3O and 3P.

Torsion of a space curve: The torsion at a point of a space curve is themagnitude of the rate of change of the binormal unit vector at thatpoint. It measures how much the curve deviates from the osculatingplane. A space curve which lies in a plane has zero torsion. A spacecurve which deviates a relatively small amount from the osculating planewill have a relatively small magnitude of torsion (e.g. a gently slopinghelical path). A space curve which deviates a relatively large amountfrom the osculating plane will have a relatively large magnitude oftorsion (e.g. a steeply sloping helical path). With reference to FIG.3S, since T2>T1, the magnitude of the torsion near the top coils of thehelix of FIG. 3S is greater than the magnitude of the torsion of thebottom coils of the helix of FIG. 3S

With reference to the right-hand rule of FIG. 3P, a space curve turningtowards the direction of the right-hand binormal may be considered ashaving a right-hand positive torsion (e.g. a right-hand helix as shownin FIG. 3S). A space curve turning away from the direction of theright-hand binormal may be considered as having a right-hand negativetorsion (e.g. a left-hand helix).

Equivalently, and with reference to a left-hand rule (see FIG. 3O), aspace curve turning towards the direction of the left-hand binormal maybe considered as having a left-hand positive torsion (e.g. a left-handhelix). Hence left-hand positive is equivalent to right-hand negative.See FIG. 3T.

5.9.6.4 Holes

A surface may have a one-dimensional hole, e.g. a hole bounded by aplane curve or by a space curve. Thin structures (e.g. a membrane) witha hole, may be described as having a one-dimensional hole. See forexample the one dimensional hole in the surface of structure shown inFIG. 31 , bounded by a plane curve.

A structure may have a two-dimensional hole, e.g. a hole bounded by asurface. For example, an inflatable tyre has a two dimensional holebounded by the interior surface of the tyre. In another example, abladder with a cavity for air or gel could have a two-dimensional hole.See for example the cushion of FIG. 3L and the example cross-sectionstherethrough in FIG. 3M and FIG. 3N, with the interior surface boundinga two dimensional hole indicated. In a yet another example, a conduitmay comprise a one-dimension hole (e.g. at its entrance or at its exit),and a two-dimension hole bounded by the inside surface of the conduit.See also the two dimensional hole through the structure shown in FIG.3K, bounded by a surface as shown.

5.10 OTHER REMARKS

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in Patent Office patent files orrecords, but otherwise reserves all copyright rights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Furthermore, “approximately”, “substantially”, “about”, or any similarterm as used herein means+/−5-10% of the recited value.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being used to construct acomponent, obvious alternative materials with similar properties may beused as a substitute. Furthermore, unless specified to the contrary, anyand all components herein described are understood to be capable ofbeing manufactured and, as such, may be manufactured together orseparately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated herein by referencein their entirety to disclose and describe the methods and/or materialswhich are the subject of those publications. The publications discussedherein are provided solely for their disclosure prior to the filing dateof the present application. Nothing herein is to be construed as anadmission that the present technology is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dates,which may need to be independently confirmed.

The terms “comprises” and “comprising” should be interpreted asreferring to elements, components, or steps in a non-exclusive manner,indicating that the referenced elements, components, or steps may bepresent, or utilized, or combined with other elements, components, orsteps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular examples, it is to be understood that these examples aremerely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative examples and that other arrangements may be devisedwithout departing from the spirit and scope of the technology.

5.11 REFERENCE SIGNS LIST

patient 1000 area proximate ala 1010 alar crest 1020 bed partner 1100seal forming structure 3100 first seal forming structure 3101 secondseal forming structure 3102 boundary 3103 central portion 3110 lateralportion 3111 posterior surfaces of lateral portion 3112 ridge 3120 lipinferior portion 3130 lip superior portion 3131 peripheral portion 3132oral hole 3133 nasal aperture(s) 3135 first material 3150 secondmaterial 3152 corner 3153 transition 3154 plenum chamber 3200 oralportion of plenum chamber 3201 nasal portion or plenum, chamber 3202chord 3210 superior point 3220 inferior point 3230 first anterior wallportion 3240 boundary of oral and nasal portion 3241 second anteriorwall portion 3242 first anterior wall portion superior 3243 boundaryfirst anterior wall portion inferior 3244 boundary lateral side wallportion 3245 lateral side wall portion 3246 second anterior wall portionsuperior 3247 boundary second anterior wall portion inferior 3248boundary shell 3250 central portion 3251 support portions 3260 first endof support portion 3261 second end of support portion 3262 rigid portion3263 band 3270 cavity 3272 groove 3280 projection 3284 protrusion 3288mounting flange 3290 first free end 3291 second free end 3292 gap 3293overhang 3294 lower surface 3295 upper surface 3296 positioning andstabilising structure 3300 frame 3350 connection point 3352 first loop 3352a second loop  3352b headgear straps 3354 left superior headgearstrap 3356 right superior headgear strap 3358 central portion 3360 arm3362 secondary connection point 3364 left secondary connection point 3364a right secondary connection point  3364b left inferior strap 3366right inferior strap 3368 magnet 3370 slot 3372 connectors 3310 arms3320 vent 3400 vent mounting aperture 3410 connection port 3600 straightsurface 3604 forehead support 3700 RPT device 4000 external housing 4010upper portion 4012 lower portion 4014 panel 4015 chassis 4016 handle4018 pneumatic block 4020 air filter 4110 inlet air filter 4112 muffler4120 outlet muffler 4124 pressure generator 4140 blower 4142 motor 4144anti-spillback valve 4160 air circuit 4170 supplementary gas 4180electrical components 4200 PCBA 4202 electrical power supply 4210 inputdevice 4220 transducers 4270 humidifier 5000 humidifier inlet 5002humidifier outlet 5004 humidifier base 5006 humidifier reservoir 5110conductive portion 5120 reservoir dock 5130 locking lever 5135 waterlevel indicator 5150 heating element 5240

1-49. (canceled)
 50. A patient interface comprising: a plenum chamberpressurisable to a therapeutic pressure of at least 6 cmH2O aboveambient air pressure, the plenum chamber including a plenum chamberinlet port sized and structured to receive a flow of air at thetherapeutic pressure for breathing by a patient, wherein the plenumchamber includes a mounting surface, and wherein the mounting surface issubstantially flat; a seal-forming structure constructed and arranged toform a seal with a region of the patient's face surrounding an entranceto the patient's airways for sealed delivery of a flow of pressurizedair at the therapeutic pressure of at least 6 cmH2O above ambient airpressure throughout the patient's respiratory cycle in use, theseal-forming structure comprises: a first section constructed from afirst material, the first section configured to sealingly engage againsta first region of the patient's face, and a second section constructedfrom a second material different than the first material, the secondsection configured to sealingly engage against a second region of thepatient's face, wherein the second material is foam, and wherein thesecond section of the seal-forming structure is coupled to the mountingsurface, a positioning and stabilising structure to provide a force tohold a seal-forming structure in a therapeutically effective position ona patient's head, and wherein the first section and the plenum chamberare integrally formed as a one-piece construction during a moldingprocess.
 51. The patient interface of claim 50, wherein the firstmaterial is silicone.
 52. The patient interface of claim 50, wherein thefirst section is flush with the second section at a transition betweenthe first section and the second section.
 53. The patient interface ofclaim 50, wherein the mounting surface is configured to be orientedsubstantially perpendicular to an anterior-posterior direction of thepatient's head, in use.
 54. The patient interface of claim 50, whereinthe mounting surface is constructed from the first material.
 55. Thepatient interface of claim 50, wherein the first section extends beyondthe mounting surface, and forms an overhang relative to the mountingsurface.
 56. The patient interface of claim 50, wherein the overhang isconfigured to contact the patient proximate each nasal ala.
 57. Thepatient interface of claim 50, wherein the plenum chamber inlet port isformed anterior to the mounting surface, in use, and wherein the secondmaterial does not contact the plenum chamber inlet port.
 58. The patientinterface of claim 50, wherein the mounting surface is substantiallyU-shaped or C-shaped and includes a first free end and a second freeend, and wherein, in use, the first free end is configured to be spacedapart from the second free end along the patient's lip superior so as toleave the patient's philtrum uncovered by the mounting surface.
 59. Thepatient interface of claim 50, wherein the plenum chamber is at leastpartially constructed from the first material.
 60. The patient interfaceof claim 50, wherein the second section is coupled to the plenum chamberwith an adhesive.
 61. The patient interface of claim 50, wherein thesecond section includes a varying thickness.
 62. The patient interfaceof claim 61, wherein the second section includes a first thickness and asecond thickness greater than the first thickness, wherein the firstthickness is adjacent to the second thickness.
 63. The patient interfaceof claim 50, wherein the seal-forming structure is configured to form aseal against the patient's face, wherein first section and the secondsection each combine to form a portion of the seal.
 64. The patientinterface of claim 50, wherein the seal-forming structure is a nasalcushion or a nasal cradle.
 65. The patient interface of claim 64,wherein the second section is configured to contact a nasal alar regionof the patient, in use.
 66. The patient interface of claim 50, whereinthe seal-forming structure is an oronasal cushion, an ultra-compact fullface mask, or a full-face mask.
 67. The patient interface of claim 66,wherein the first section is configured to contact the patient's nose,in use, between at least the patient's pronasale and the patient'ssubnasale, and between at least each of the patient's nasal ala.
 68. Thepatient interface of claim 66, wherein the second section is configuredto contact around the patient's mouth, in use, between at least thepatient's lip superior and the patient's lip inferior, and outside ofthe patient's mouth width adjacent at least each of the patient's nasalala.
 69. The patient interface of claim 66, wherein a bridge portion ofthe second section is configured to contact the patient's lip superiorin use.
 70. The patient interface of claim 69, wherein at least aportion of the bridge portion is unbacked, and is configured to moveinto the plenum chamber when contacted by the patient's lip superior.71. The patient interface of claim 69, wherein the transition is betweenthe bridge portion and the first section.
 72. The patient interface ofclaim 66, wherein the seal-forming structure is configured to not sealagainst the patient's philtrum.
 73. The patient interface of claim 66,wherein a portion of the second section is configured to seal against aregion inferior to the patient's nares and proximate to the patient'snasal ala.
 74. The patient interface of claim 66, wherein the firstsection is thinner than the second section.
 75. The patient interface ofclaim 66, wherein, when viewed in cross-section, the second section hasa substantially rectangular profile.
 76. The patient interface of claim66, wherein the second section includes a substantially squared edgeconfigured to contact the patient in use.
 77. The patient interface ofclaim 76, wherein the substantially squared edge is configured tocontact the proximate the nasal ala at a juncture of the patient'scorner of nose region and the patient's lip superior.
 78. The patientinterface of claim 50, wherein the first section is configured toreceive a first component of the force and the second section isconfigured to receive a second component of the force, wherein the firstsection and the second section are configured to apply the same sealingforce to the patient when the first component is less than the secondcomponent.